scsi: qla2xxx: Only allow operational MBX to proceed during RESET.

This patch is allowing only ROM mailbox command which are
necessary to initialize chip after a reset has been issued.
In a target environment, there could be a user space daemon
which can issue statistics and other management mailbox command
which are non-critical. This patch will timeout non critical
mailbox commands immediately rather than waiting for timeout,
if driver detects that chip reset has been issued or chip reset
is in progress.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Giridhar Malavali <giridhar.malavali@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>