[media] omap3isp: Use a local media device pointer instead

The function has a local variable that points to the media device; use
that instead of finding the media device under the entity.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/omap3isp/ispvideo.c

@@ -232,7 +232,7 @@ static int isp_video_get_graph_data(struct isp_video *video,
 	int ret;
 
 	mutex_lock(&mdev->graph_mutex);
-	ret = media_graph_walk_init(&graph, entity->graph_obj.mdev);
+	ret = media_graph_walk_init(&graph, mdev);
 	if (ret) {
 		mutex_unlock(&mdev->graph_mutex);
 		return ret;