scsi: aacraid: Remove erroneous fallthrough annotation

This fallthrough annotation is unreachable so we can delete it.

Link: https://lore.kernel.org/r/20200825112003.GD285523@mwanda


Fixes: c4e2fbca ("scsi: aacraid: Reworked scsi command submission path")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>