scsi: aacraid: remove redundant zero check on ret

The check for ret being zero is redundant as a few statements earlier we
break out of the while loop if ret is non-zero.  Thus we can remove the
zero check and also the dead-code non-zero case too.

Detected by CoverityScan, CID#1411632 ("Logically Dead Code")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Dave Carroll <david.carroll@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>