tape: beyond ARRAY_SIZE of viocd_diskinfo

Do not go beyond ARRAY_SIZE of tape_device and viotape_unitinfo

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/drivers/char/viotape.c b/drivers/char/viotape.c
index ffc9254..042c814 100644
--- a/drivers/char/viotape.c
+++ b/drivers/char/viotape.c
@@ -867,7 +867,7 @@
 	int j;
 	struct device_node *node = vdev->dev.archdata.of_node;
 
-	if (i > VIOTAPE_MAX_TAPE)
+	if (i >= VIOTAPE_MAX_TAPE)
 		return -ENODEV;
 	if (!node)
 		return -ENODEV;