scsi: lpfc: correct nvme sg segment count check

The internal cfg flag is actually smaller, by 1 (for a partial page
sge), than the sg list maintained by the driver. Thus the check on sg
segments errored out when it shouldn't have

Ensure the check is +1

Note: having a value that is less than what it really is is bogus.
Correcting it now would be a significant rework. Add this item to the
list to be refactored in the merge with efct.

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>