MFC all cxgbe(4) changes missing from stable/9:
r248925, r249368, r249370, r249376, r249382, r249383, r249385, r249391,
r249392, r249393, r249627, r249629, r250090, r250092, r250093, r250117,
r250218, r250221, r250614, r251213, r251317, r251358, r251434, r251518,
r251638, r252312, r252469, r252470, r250697(kib).

r248925:
Support for Chelsio's 40G Terminator 5 (aka T5) ASIC.
...

r249368:
Set and display the IP fragment bit correctly when dealing with
the filter mode.

r249370:
cxgbe(4): Ensure that the MOD_LOAD handler runs before either t4nex or
t5nex attach to their devices.

r249376:
- Explain clearly why a different firmware is being installed (if/when
  it is being installed).  Improve other error messages while here.

- Select special FPGA specific configuration profile when appropriate.

r249382:
There is no need for elaborate queries and error checking when trying to
set FW4MSG_ENCAP.

r249383:
Get rid of a couple of stray \n's.

r249385:
cxgbe/tom: Slight simplification of code that calculates options2.

r249391:
Auto-reduce the holdoff timers that are greater than the maximum value
allowed by the hardware.

r249392:
Cosmetic change (s/wrwc/wcwr/;s/WRWC/WCWR/).

r249393:
Add pciids of the T5 based cards.  The ones that I haven't tested with
cxgbe(4) are disabled for now.  This will change.

r249627:
cxgbe/tom: Update the CLIP table on the chip when there are changes
to the list of IPv6 addresses on the system.  The table is used for
TOE+IPv6 only.

r249629:
cxgbe(4): Refuse to install T5 firmwares on a T4 card (and vice versa).

r250090:
cxgbe(4): Some updates to shared code.

r250092:
- Provide accurate ifmedia information so that 40G ports/transceivers are
  displayed properly in ifconfig, etc.

- Use the same number of tx and rx queues for a 40G port as for a 10G port.

r250093:
Attach to the T580 (2 x 40G) card.

r250117:
Fix DDP breakage introduced in r248925.  Bitwise OR has higher
precedence than ternary conditional.

r250218:
cxgbe/tom: Do not use M_PROTO1 to mark rx zero-copy mbufs as special.
All the M_PROTOn flags are clobbered when an mbuf is appended to the
socket buffer.

r250221:
cxgbe: Switch to a better way to install firmware.

r250614:
Deal correctly with 40G ports that don't have any transceiver plugged
in.  Do not claim that they have unknown tranceivers.

r251213:
cxgbe(4): Some more debug sysctls.  These work on both T4 and T5 based
cards.

r251317:
cxgbe(4): t4fw_cfg must be explicitly loaded if the driver is being
loaded via loader.conf.

r251358:
cxgbe(4): Provide accurate hit count for filters on T5 cards.  The
location within the TCB and the size have both changed.

r251434:
cxgbe(4): Never install a firmware if hw.cxgbe.fw_install is 0.

r251518:
cxgbe/tom: Fix bad signed/unsigned mixup in the stid allocator.  This
fixes a panic when allocating a mixture of IPv6 and IPv4 stids.

r251638:
cxgbe/tom: Allow caller to select the queue (control or data) used to
send the CPL_SET_TCB_FIELD request in t4_set_tcb_field().

r252312:
Update T5 register ranges.  This is so that regdump skips over registers
with read side-effects.

r252469:
Add a sysctl to get the number of filters available.

sysctl dev.t4nex.<N>.nfilters
sysctl dev.t5nex.<N>.nfilters

r252470:
Count the number of hits for a filter by default.

r250697:
Add dependencies on the firmware, which allows the loading of the cxgb
and cxgbe modules.
MFC r251960:
Since the gem pagefault handler relocks the vm object lock, other
thread might fault on the same GTT offset meantime and instantiate the
mapping.  Recheck that the mgt device object still does not have a
page at the current offset after relocking, and return a possibly
installed page.
MFC r251961:
Disable wait for the retrace if KMS is activated.