scsi: aic7xxx: Fix error code handling

ahc_linux_queue_recovery_cmd returns SUCCESS(0x2002) or FAIL(0x2003), but
the caller is checking error case using != 0.

Link: https://lore.kernel.org/r/20200816070242.978839-1-ztong0001@gmail.com


Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>