Some clean up with helper fucntion

Merge series from Zhang Zekun <zhangzekun11@huawei.com>:

There are some helper functions which can be used to simplify the code.
So, let's use these functions to make code more simple.

sound/soc/generic/audio-graph-card.c

@@ -361,7 +361,6 @@ static int __graph_for_each_link(struct simple_util_priv *priv,
 	struct device *dev = simple_priv_to_dev(priv);
 	struct device_node *node = dev->of_node;
 	struct device_node *cpu_port;
-	struct device_node *cpu_ep;
 	struct device_node *codec_ep;
 	struct device_node *codec_port;
 	struct device_node *codec_port_old = NULL;
@@ -371,14 +370,9 @@ static int __graph_for_each_link(struct simple_util_priv *priv,
 	/* loop for all listed CPU port */
 	of_for_each_phandle(&it, rc, node, "dais", NULL, 0) {
 		cpu_port = it.node;
-		cpu_ep	 = NULL;
 
 		/* loop for all CPU endpoint */
-		while (1) {
-			cpu_ep = of_get_next_child(cpu_port, cpu_ep);
-			if (!cpu_ep)
-				break;
-
+		for_each_child_of_node_scoped(cpu_port, cpu_ep) {
 			/* get codec */
 			codec_ep = of_graph_get_remote_endpoint(cpu_ep);
 			codec_port = ep_to_port(codec_ep);
@@ -408,10 +402,8 @@ static int __graph_for_each_link(struct simple_util_priv *priv,
 			of_node_put(codec_ep);
 			of_node_put(codec_port);
 
-			if (ret < 0) {
-				of_node_put(cpu_ep);
+			if (ret < 0)
 				return ret;
-			}
 
 			codec_port_old = codec_port;
 		}

sound/soc/generic/audio-graph-card2.c

@@ -1139,21 +1139,12 @@ static int graph_counter(struct device_node *lnk)
 	 */
 	if (graph_lnk_is_multi(lnk)) {
 		struct device_node *ports = port_to_ports(lnk);
-		struct device_node *port = NULL;
-		int cnt = 0;
 
 		/*
 		 * CPU/Codec = N:M case has many endpoints.
 		 * We can't use of_graph_get_endpoint_count() here
 		 */
-		while(1) {
-			port = of_get_next_child(ports, port);
-			if (!port)
-				break;
-			cnt++;
-		}
-
-		return cnt - 1;
+		return of_get_child_count(ports) - 1;
 	}
 	/*
 	 * Single CPU / Codec