cxgb4: FW upgrade fixes

Disable FW_OK flag while flashing Firmware. This will help to fix any
potential mailbox timeouts during Firmware flash.

Grab new devlog parameters after Firmware restart. When we FLASH new
Firmware onto an adapter, the new Firmware may have the Firmware Device Log
located at a different memory address or have a different size for it.

Signed-off-by: Arjun Vynipadath <arjun@chelsio.com>
Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>