[media] davinci: 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: NSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/staging/media/davinci_vpfe/vpfe_video.c

@@ -145,7 +145,7 @@ static int vpfe_prepare_pipeline(struct vpfe_video_device *video)
 		pipe->outputs[pipe->output_num++] = video;
 
 	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 -ENOMEM;
@@ -300,7 +300,7 @@ static int vpfe_pipeline_enable(struct vpfe_pipeline *pipe)
 
 	mdev = entity->graph_obj.mdev;
 	mutex_lock(&mdev->graph_mutex);
-	ret = media_graph_walk_init(&pipe->graph, entity->graph_obj.mdev);
+	ret = media_graph_walk_init(&pipe->graph, mdev);
 	if (ret)
 		goto out;
 	media_graph_walk_start(&pipe->graph, entity);