scsi: qedi: Fix a potential buffer overflow

Tell snprintf() to store at most 255 characters in the output buffer
instead of 256. This patch avoids that smatch reports the following
warning:

drivers/scsi/qedi/qedi_main.c:891: qedi_get_boot_tgt_info() error: snprintf() is printing too much 256 vs 255
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: <QLogic-Storage-Upstream@cavium.com>
Cc: <stable@vger.kernel.org>
Acked-by: Nilesh Javali <nilesh.javali@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qedi/qedi_main.c

@@ -888,7 +888,7 @@ static void qedi_get_boot_tgt_info(struct nvm_iscsi_block *block,
 	ipv6_en = !!(block->generic.ctrl_flags &
 		     NVM_ISCSI_CFG_GEN_IPV6_ENABLED);
 
-	snprintf(tgt->iscsi_name, NVM_ISCSI_CFG_ISCSI_NAME_MAX_LEN, "%s\n",
+	snprintf(tgt->iscsi_name, sizeof(tgt->iscsi_name), "%s\n",
 		 block->target[index].target_name.byte);
 
 	tgt->ipv6_en = ipv6_en;