cxgb4: collect firmware mbox and device log dump

Collect firmware mbox and device logs before collecting the rest of
the hardware dumps to snap the firmware state before the mailbox logs
are updated by other hardware dumps.

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>