[media] v4l: vsp1: wpf: Simplify cast to pipeline structure

Use the subdev pointer directly to_vsp1_pipeline() macro instead of
casting from the subdev to the wpf object and back to the subdev.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/drivers/media/platform/vsp1/vsp1_wpf.c b/drivers/media/platform/vsp1/vsp1_wpf.c
index 36c4793..591f09c 100644
--- a/drivers/media/platform/vsp1/vsp1_wpf.c
+++ b/drivers/media/platform/vsp1/vsp1_wpf.c
@@ -44,9 +44,8 @@
 
 static int wpf_s_stream(struct v4l2_subdev *subdev, int enable)
 {
+	struct vsp1_pipeline *pipe = to_vsp1_pipeline(&subdev->entity);
 	struct vsp1_rwpf *wpf = to_rwpf(subdev);
-	struct vsp1_pipeline *pipe =
-		to_vsp1_pipeline(&wpf->entity.subdev.entity);
 	struct vsp1_device *vsp1 = wpf->entity.vsp1;
 	const struct v4l2_rect *crop = &wpf->crop;
 	unsigned int i;