RDMA/cxgb4: Don't hang threads forever waiting on WR replies

In c4iw_wait_for_reply(), if a FW6_MSG WR reply is not received after
C4IW_WR_TO seconds, fail the WR operation and mark the device as fatally
dead.  Further, if the device is marked fatally dead, then fail the WR
wait immediately.

Also change the timeout to 60 seconds.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>