MFC r228491, r228561, r228594.

MFC r228491, r228561, r228594.

r228491:
Do not clobber the ingress queue's congestion setting.

r228561:
Many updates to cxgbe(4)

- Device configuration via plain text config file.  Also able to operate
  when not attached to the chip as the master driver.

- Generic "work request" queue that serves as the base for both ctrl and
  ofld tx queues.

- Generic interrupt handler routine that can process any event on any
  kind of ingress queue (via a dispatch table).

- A couple of new driver ioctls.  cxgbetool can now install a firmware
  to the card ("loadfw" command) and can read the card's memory
  ("memdump" and "tcb" commands).

- Lots of assorted information within dev.t4nex.X.misc.*  This is
  primarily for debugging and won't show up in sysctl -a.

- Code to manage the L2 tables on the chip.

- Updates to cxgbe(4) man page to go with the tunables that have changed.

- Updates to the shared code in common/

- Updates to the driver-firmware interface (now at fw 1.4.16.0)

r228594:
Catch up with new driver ioctls in cxgbe.

git-svn-id: svn://svn.freebsd.org/base/stable/8@231103 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f