scsi: lpfc: Use correct scnprintf() limit

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: 5b9e70b22c ("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>

drivers/scsi/lpfc/lpfc_attr.c

@@ -6204,7 +6204,8 @@ lpfc_sg_seg_cnt_show(struct device *dev, struct device_attribute *attr,
 	len = scnprintf(buf, PAGE_SIZE, "SGL sz: %d  total SGEs: %d\n",
 		       phba->cfg_sg_dma_buf_size, phba->cfg_total_seg_cnt);
 
-	len += scnprintf(buf + len, PAGE_SIZE, "Cfg: %d  SCSI: %d  NVME: %d\n",
+	len += scnprintf(buf + len, PAGE_SIZE - len,
+			"Cfg: %d  SCSI: %d  NVME: %d\n",
 			phba->cfg_sg_seg_cnt, phba->cfg_scsi_seg_cnt,
 			phba->cfg_nvme_seg_cnt);
 	return len;