cdrom: beyond ARRAY_SIZE of viocd_diskinfo

Do not go beyond ARRAY_SIZE of viocd_diskinfo

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/cdrom/viocd.c b/drivers/cdrom/viocd.c
index 1392935..9b1624e 100644
--- a/drivers/cdrom/viocd.c
+++ b/drivers/cdrom/viocd.c
@@ -587,7 +587,7 @@
 	struct device_node *node = vdev->dev.archdata.of_node;
 
 	deviceno = vdev->unit_address;
-	if (deviceno > VIOCD_MAX_CD)
+	if (deviceno >= VIOCD_MAX_CD)
 		return -ENODEV;
 	if (!node)
 		return -ENODEV;