media: v4l: vsp1: Fix uif null pointer access

RZ/G2L SoC has no UIF. This patch fixes null pointer access, when UIF
module is not used.

Fixes: 5e824f98("media: v4l: vsp1: Integrate DISCOM in display pipeline")
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/vsp1/vsp1_drm.c

@@ -462,9 +462,9 @@ static int vsp1_du_pipeline_setup_inputs(struct vsp1_device *vsp1,
 	 * make sure it is present in the pipeline's list of entities if it
 	 * wasn't already.
 	 */
-	if (!use_uif) {
+	if (drm_pipe->uif && !use_uif) {
 		drm_pipe->uif->pipe = NULL;
-	} else if (!drm_pipe->uif->pipe) {
+	} else if (drm_pipe->uif && !drm_pipe->uif->pipe) {
 		drm_pipe->uif->pipe = pipe;
 		list_add_tail(&drm_pipe->uif->list_pipe, &pipe->entities);
 	}