Zero the planes array before queuing buffers

V4L2 requires reserved fields to be zeroed.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
diff --git a/yavta.c b/yavta.c
index 930645d..7d8ac8e 100644
--- a/yavta.c
+++ b/yavta.c
@@ -965,6 +965,8 @@
 	unsigned int i;
 
 	memset(&buf, 0, sizeof buf);
+	memset(&planes, 0, sizeof planes);
+
 	buf.index = index;
 	buf.type = dev->type;
 	buf.memory = dev->memtype;