scsi: libfc: Remove an unneeded condition

We verified that resp_code is FC_SPP_RESP_ACK earlier so we don't need
to check again here.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>