scsi: lpfc: Use correct scnprintf() limit

[ Upstream commit 6dacc371 ]

The limit should be "PAGE_SIZE - len" instead of "PAGE_SIZE".  We're not
going to hit the limit so this fix will not affect runtime.

Link: https://lore.kernel.org/r/20210916132331.GE25094@kili
Fixes: 5b9e70b2

 ("scsi: lpfc: raise sg count for nvme to use available sg resources")
Reviewed-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>