scsi: mpt3sas: Fix Coverity reported issue

Fix the structurally dead code (UNREACHABLE) type of error reported by
Coverity.

Link: https://lore.kernel.org/r/20210618155506.2609112-1-suganath-prabu.subramani@broadcom.com


Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>