linux compat: add SO_PASSCRED option with basic handling

This seems to have been a part of a bigger patch by dchagin that either
haven't been committed or committed partially.

Submitted by:	dchagin, nox
MFC after:	2 weeks
If 802.11n is enabled, bump the number of buffers used up to a larger
level.

This is important for AMPDU RX as each burst is multiple packets in a row.
This was missing from the previous HAL commit - it fixes a typo and
introduces the PS-POLL hardware support.
.. And another missed commit - add the PSPOLL capability.
Cause the release target to set up its object directory. It is designed
to be a meta-target, and having it do this avoids it spewing files all
over the source tree by default (and possible recursive tarring if
distributing a src tarball).
- Merge the *_SET macros from fire(4) which generally print out the
  register changes when compiled with SCHIZO_DEBUG and take advantage
  of them.
- Add support for the XMITS Fireplane/Safari to PCI-X bridges. I tought
  I'd need this for a Sun Fire 3800, which then turned out to not being
  equipped with such a bridge though. The support for these should be
  complete but given that it hasn't actually been tested probing is
  disabled for now.
  This required a way to alter the XMITS configuration in case a PCI-X
  device is found further down the device tree so the sparc64 specific
  ofw_pci kobj was revived with a ofw_pci_setup_device method, which is
  called by the ofw_pcibus code for every device added.
- A closer inspection of the OpenSolaris code indicates that consistent
  DMA flushing/syncing as well as the block store workaround should be
  applied with every BUS_DMASYNC_POSTREAD instead of in a wrapper around
  interrupt handlers for devices behind PCI-PCI bridges only as suggested
  by the documentation (code for the latter actually exists in OpenSolaris
  but is disabled by default), which also makes more sense.
- Add a workaround for Casinni/Skyhawk combinations. Chances are that
  this solves the crashes seen when using the the on-board Casinni NICs
  of Sun Fire V480 equipped with centerplanes other than 501-6780 or
  501-6790. This also takes advantage of the ofw_pci_setup_device method.
- Mark some unused parameters as such.
- A closer inspection of the OpenSolaris code indicates that the DMA
  syncing for Hummingbird and Sabre bridges should be applied with every
  BUS_DMASYNC_POSTREAD instead of in a wrapper around interrupt handlers
  for devices behind PCI-PCI bridges only as suggested by the documentation
  (code for the latter actually exists in OpenSolaris but is disabled by
  default), which also makes more sense.
- Take advantage of the ofw_pci_setup_device method introduced in r220038
  for disabling bus parking for certain EBus bridges in order to
- Mark some unused parameters as such.
Fix some style issues in r219925.

Reported by:	bde
MFC after:	1 month
Fixed sockets display somewhat (-L, -T, -x, -Lx, with and without -A).
(I didn't try to fix negative TCP timers with -x.)

MFC after:	3 days
Eliminate an unused definition.

Reviewed by:	marcel
Print the raw value of si_code, that is esp. useful for undecoded values.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Wait until the DMA engine is stopped before unmapping buffers and
descriptors, which fixes DMA errors seen on sparc64.

Obtained from:	OpenBSD
MFC after:	1 week
Add svn:executable property on remaining period scripts without it
Hook the 220.backup-pkgdb script I added to the build unconditionally

Hook up 610.ipf6denied based on MK_IPFILTER as 510.ipfdenied is now

Poked by:	Andrzej Tobola <ato@iem.pw.edu.pl>
Add some missing flags needed for AR913x/AR724x USB to correctly operate.

The AR913x/AR724x USB lives at a different offset to the AR71xx
USB, so this needs to be either adjusted for in a subsequent
commit, or updated in hints for kernels compiled for those
platforms.

Submitted by: Luiz Otavio O Souzau <loos.br@gmail.com>
Add an option - AR71XX_REALMEM - which overrides the amount of
memory detected from Redboot, or overrides the "otherwise" case
if no Redboot information was found.

Some AR71XX platforms don't use Redboot (eg TP-LINK devices using
UBoot; some later Ubiquiti devices which apparently also use
UBoot) and at least one plain out lies - the Ubiquiti LS-SR71A
Redboot says there's 16mb of RAM when in fact there's 32mb.

A more "clean" solution will be needed at a later date.
Rename AH_ENABLE_11N to ATH_ENABLE_11 - the HAL supports 11n by
default but the ath driver doesn't. This is a much more consistent
name.
Fix typo.
getpwnam(3) may return NULL.

Requested by:   nork
Reviewed by:    Takeharu KATO <takeharu1219__at__ybb.ne.jp>, nork
MFC after:      1 week
Refactor out the ar71xx mac address code into something that's
just for Redboot.

At some point we're going to need to build options for different
boot environments - for example, the UBoot setups I've seen simply
have the MAC address hard-coded at a fixed location in flash.
The OpenWRT support simply yanks the if_arge MAC directly from that
in code, rather than trying to find a uboot environment to pull it
from.