bnxt_en: Abort waiting for firmware response if there is no heartbeat.

This is especially beneficial during the NVRAM related firmware
commands that have longer timeouts.  If the BNXT_STATE_FW_FATAL_COND
flag gets set while waiting for firmware response, abort and return
error.

Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>