drm/imx: use for_each_endpoint_of_node macro in imx_drm_encoder_get_mux_id

Using the for_each_... macro should make the code bit shorter and
easier to read. This patch also properly decrements the endpoint node
reference count before returning out of the loop.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/drm/imx/imx-drm-core.c

@@ -439,7 +439,7 @@ int imx_drm_encoder_get_mux_id(struct device_node *node,
 			       struct drm_encoder *encoder)
 {
 	struct imx_drm_crtc *imx_crtc = imx_drm_find_crtc(encoder->crtc);
-	struct device_node *ep = NULL;
+	struct device_node *ep;
 	struct of_endpoint endpoint;
 	struct device_node *port;
 	int ret;
@@ -447,18 +447,15 @@ int imx_drm_encoder_get_mux_id(struct device_node *node,
 	if (!node || !imx_crtc)
 		return -EINVAL;
 
-	do {
-		ep = of_graph_get_next_endpoint(node, ep);
-		if (!ep)
-			break;
-
+	for_each_endpoint_of_node(node, ep) {
 		port = of_graph_get_remote_port(ep);
 		of_node_put(port);
 		if (port == imx_crtc->crtc->port) {
 			ret = of_graph_parse_endpoint(ep, &endpoint);
+			of_node_put(ep);
 			return ret ? ret : endpoint.port;
 		}
-	} while (ep);
+	}
 
 	return -EINVAL;
 }