scsi: lpfc: Fix relative offset error on large nvmet target ios

If the nvmet_fc transport breaks an io into multiple sequences, the
driver will improperly set the relative offset on the 2nd through N
sequences.

Correct by properly formatting the hw cmd so the relative offset is
picked up from the hw cmd.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>