drm/sun4i: tcon: Release node when traversing of graph

Function sun4i_tcon_find_engine_traverse() doesn't release node if it
needs to traverse of graph deeper than 1 level.

Fix this by calling of_node_put().

Fixes: 49836b11 ("drm/sun4i: tcon: Generalize engine search algorithm")
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180710203511.18454-6-jernej.skrabec@siol.net

drivers/gpu/drm/sun4i/sun4i_tcon.c

@@ -811,6 +811,7 @@ sun4i_tcon_find_engine_traverse(struct sun4i_drv *drv,
 	 * remote output id. If this for some reason can't be done, 0
 	 * is used as input port id.
 	 */
+	of_node_put(port);
 	port = of_graph_get_remote_port(ep);
 	if (!of_property_read_u32(port, "reg", &reg) && reg > 0)
 		reg -= 1;