[media] rcar-vin: get rid of an unused var

drivers/media/platform/rcar-vin/rcar-core.c: In function 'rvin_graph_notify_complete':
drivers/media/platform/rcar-vin/rcar-core.c:65:22: warning: variable 'sd' set but not used [-Wunused-but-set-variable]
  struct v4l2_subdev *sd;
                      ^
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/rcar-vin/rcar-core.c

@@ -62,12 +62,9 @@ static int rvin_mbus_supported(struct rvin_dev *vin)
 
 static int rvin_graph_notify_complete(struct v4l2_async_notifier *notifier)
 {
-	struct v4l2_subdev *sd;
 	struct rvin_dev *vin = notifier_to_vin(notifier);
 	int ret;
 
-	sd = vin_to_source(vin);
-
 	ret = v4l2_device_register_subdev_nodes(&vin->v4l2_dev);
 	if (ret < 0) {
 		vin_err(vin, "Failed to register subdev nodes\n");