Add initial support for the AR9485 CUS198 / CUS230 variants.

These variants have a few differences from the default AR9485 NIC,
namely:

* a non-default antenna switch config;
* slightly different RX gain table setup;
* an external XLNA hooked up to a GPIO pin;
* (and not yet done) RSSI threshold differences when
  doing slow diversity.

To make this possible:

* Add the PCI device list from Linux ath9k, complete with vendor and
  sub-vendor IDs for various things to be enabled;
* .. and until FreeBSD learns about a PCI device list like this,
  write a search function inspired by the USB device enumeration code;
* add HAL_OPS_CONFIG to the HAL attach methods; the HAL can use this
  to initialise its local driver parameters upon attach;
* copy these parameters over in the AR9300 HAL;
* don't default to override the antenna switch - only do it for
  the chips that require it;
* I brought over ar9300_attenuation_apply() from ath9k which is cleaner
  and easier to read for this particular NIC.

This is a work in progress.  I'm worried that there's some post-AR9380
NIC out there which doesn't work without the antenna override set as
I currently haven't implemented bluetooth coexistence for the AR9380
and later HAL.  But I'd rather have this code in the tree and fix it
up before 11.0-RELEASE happens versus having a set of newer NICs
in laptops be effectively RX deaf.

Tested:

* AR9380 (STA)
* AR9485 CUS198 (STA)

Obtained from:	Qualcomm Atheros, Linux ath9k
Remove this stuff - it's no longer needed here.
Make clear in the ipheth(4) hardware notes that this driver is for the
tethering functionality only.  Add a "bugs" section to give a pointer
to usbconfig set_config if the device isn't automatically detected.

MFC after:	3 days
Add a missing file from the last commit.

Noticed by: jhibbits
When plen != ulen, it should only be checked when this is UDP.

Spotted by:	bryanv
Style fixes.
Be prepared that set_dumper() might fail even when resetting it or prefix
the call with (void) to document that we intentionally ignore the return
value - no way to handle an error in case of device disappearing.
Remove redundant call to ipsec_getpolicybyaddr().
ipsec_hdrsiz() will call it internally.

Sponsored by:	Yandex LLC
Make sure __ARM_ARCH is defined in sysreg.h by including acle-compat.h
Fix pkill unit tests.

- use daemon(8) to write out a pid file for processes,
  and check for for the existence of that file after
  killing processes
- use explict named parameters to jail(8)
Fix old iSCSI initiator to work with new CAM locking.

This switches code to using xpt_scan() routine, irrelevant to locking.
Using xpt_action() directly requires knowledge about higher level locks,
that SIM does not need to have.

This code is obsoleted, but that is not a reason to crash.

MFC after:	3 days
msi: add Xen MSI implementation

This patch adds support for MSI interrupts when running on Xen. Apart
from adding the Xen related code needed in order to register MSI
interrupts this patch also makes the msi_init function a hook in
init_ops, so different MSI implementations can have different
initialization functions.

Sponsored by: Citrix Systems R&D

xen/interface/physdev.h:
 - Add the MAP_PIRQ_TYPE_MULTI_MSI to map multi-vector MSI to the Xen
   public interface.

x86/include/init.h:
 - Add a hook for setting custom msi_init methods.

amd64/amd64/machdep.c:
i386/i386/machdep.c:
 - Set the default msi_init hook to point to the native MSI
   initialization method.

x86/xen/pv.c:
 - Set the Xen MSI init hook when running as a Xen guest.

x86/x86/local_apic.c:
 - Call the msi_init hook instead of directly calling msi_init.

xen/xen_intr.h:
x86/xen/xen_intr.c:
 - Introduce support for registering/releasing MSI interrupts with
   Xen.
 - The MSI interrupts will use the same PIC as the IO APIC interrupts.

xen/xen_msi.h:
x86/xen/xen_msi.c:
 - Introduce a Xen MSI implementation.

x86/xen/xen_nexus.c:
 - Overwrite the default MSI hooks in the Xen Nexus to use the Xen MSI
   implementation.

x86/xen/xen_pci.c:
 - Introduce a Xen specific PCI bus that inherits from the ACPI PCI
   bus and overwrites the native MSI methods.
 - This is needed because when running under Xen the MSI messages used
   to configure MSI interrupts on PCI devices are written by Xen
   itself.

dev/acpica/acpi_pci.c:
 - Lower the quality of the ACPI PCI bus so the newly introduced Xen
   PCI bus can take over when needed.

conf/files.i386:
conf/files.amd64:
 - Add the newly created files to the build process.
xen: add the Xen implementation of pci_child_added method

Add the Xen specific implementation of pci_child_added to the Xen PCI
bus. This is needed so FreeBSD can register the devices it finds with
the hypervisor.

Sponsored by: Citrix Systems R&D

x86/xen/xen_pci.c:
 - Add the Xen pci_child_added method.
xen: make xen balloon a driver that depends on xenstore

This is done so we can prevent the Xen Balloon driver from attaching
before xenstore is setup.

Sponsored by: Citrix Systems R&D

dev/xen/balloon/balloon.c:
 - Make xen balloon a driver that depends on xenstore.
xen: move xenstore devices

Move xenstore related devices (xenstore.c and xenstore_dev.c) from
xen/xenstore to dev/xen/xenstore. This is just code motion, no
functional changes.

Sponsored by: Citrix Systems R&D
Explicitly return None for negative event indices.  Prior to this,
eventat(-1) would return the next-to-last event causing the back button
to cycle back to the end of an event source instead of stopping at the
start.
Only define the full inm_print() if KTR_IGMPV3 is enabled at compile time.
xen: defer xenstore initialization until xenstored is started

The xenstore related devices in the kernel cannot be started until
xenstored is running, which will happen later in the Dom0 case. If
start_info_t doesn't contain a valid xenstore event channel, defer all
xenstore related devices attachment to later.

Sponsored by: Citrix Systems R&D

dev/xen/xenstore/xenstore.c:
 - Prevent xenstore from trying to attach it's descendant devices if
   xenstore is not initialized.
 - Add a callback in the xenstore interrupt filter that will trigger
   the plug of xenstore descendant devices on the first received
   interrupt. This interrupt is generated when xenstored attaches to
   the event channel, and serves as a notification that xenstored is
   running.
xen: convert the xenstore user-space char device to a newbus device

Convert the xenstore user-space device (/dev/xen/xenstore) to a device
using the newbus interface. This allows us to make the device
initialization dependant on the initialization of xenstore itself in
the kernel.

Sponsored by: Citrix Systems R&D

dev/xen/xenstore/xenstore.c:
 - Convert to a newbus device, this removes the xs_dev_init function.

xen/xenstore/xenstore_internal.h:
 - Remove xs_dev_init prototype.

dev/xen/xenstore/xenstore.c:
 - Don't call xs_dev_init anymore, the device will attach itself when
   xenstore is started.
xen: add xenstored user-space device

This device is used by the user-space daemon that runs xenstore
(xenstored). It allows xenstored to map the xenstore memory page, and
reports the event channel xenstore is using.

Sponsored by: Citrix Systems R&D

dev/xen/xenstore/xenstored_dev.c:
 - Add the xenstored character device that's used to map the xenstore
   memory into user-space, and to report the event channel used by
   xenstore.

conf/files:
 - Add the device to the build process.