scsi: lpfc: Correct MDS diag and nvmet configuration

A recent change added some MDS processing in the lpfc_drain_txq routine
that relies on the fcp_wq being allocated. For nvmet operation the fcp_wq
is not allocated because it can only be an nvme-target.  When the original
MDS support was added LS_MDS_LOOPBACK was defined wrong, (0x16) it should
have been 0x10 (decimal value used for hex setting). This incorrect value
allowed MDS_LOOPBACK to be set simultaneously with LS_NPIV_FAB_SUPPORTED,
causing the driver to crash when it accesses the non-existent fcp_wq.

Correct the bad value setting for LS_MDS_LOOPBACK.

Fixes: 	ae9e28f3  ("lpfc: Add MDS Diagnostic support.")
Cc: <stable@vger.kernel.org> # v4.12+
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Tested-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>