MFC r314365

1. state checks in bxe_tx_mq_start_locked() and bxe_tx_mq_start() to sync threads during interface down or detach.
2. add sysctl to set pause frame parameters
3. increase max segs for TSO packets to BXE_TSO_MAX_SEGMENTS (32)
4. add debug messages for PHY
5. HW LRO support restricted to FreeBSD versions 8.x and above.

Submitted by: Vaishali.Kulkarni@cavium.com