Merge r334562 from stable/11 to releng/11.2. r334562 MFC'd the
following revisions to stable/11: r333650, r333652, r333682, r334406,
r334409-r334410, and r334489.

r333650:
cxgbe(4): Claim some more T5 and T6 boards.

r333652:
cxgbe(4): Add support for two more flash parts.

r333682:
cxgbe(4): Fall back to a failsafe configuration built into the firmware
if an error is reported while pre-processing the configuration file that
the driver attempted to use.

Also, allow the user to explicitly use the built-in configuration with
hw.cxgbe.config_file="built-in"

r334406:
cxgbe(4): Consider all supported speeds when building the ifmedia list
for a port. Fix other related issues while here:

• Require port lock for access to link_config.
• Allow 100Mbps operation by tracking the speed in Mbps. Yes, really.
• New port flag to indicate that the media list is immutable. It will be used in future refinements.

This also fixes a bug where the driver reports incorrect media with
recent firmwares.

r334409:
cxgbe(4): Implement ifm_change callback.

r334410:
cxgbe(4): Use ifm for ifmedia just like the rest of the kernel.

No functional change.

r334489:
cxgbe(4): Include full duplex mediaopt in media that can be reported as
active. Always report full duplex in active media.

Approved by: re@ (gjb@, kib@)
Sponsored by: Chelsio Communications