ALSA: aoa: Use helper function for_each_child_of_node()

for_each_child_of_node can help to iterate through the device_node,
and we don't need to use while loop. No functional change with this
conversion.
Signed-off-by: Zhang Zekun <zhangzekun11@huawei.com>
Link: https://patch.msgid.link/20240816021826.65190-1-zhangzekun11@huawei.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/aoa/soundbus/i2sbus/core.c

@@ -335,7 +335,7 @@ static int i2sbus_add_dev(struct macio_dev *macio,
 
 static int i2sbus_probe(struct macio_dev* dev, const struct of_device_id *match)
 {
-	struct device_node *np = NULL;
+	struct device_node *np;
 	int got = 0, err;
 	struct i2sbus_control *control = NULL;
 
@@ -347,7 +347,7 @@ static int i2sbus_probe(struct macio_dev* dev, const struct of_device_id *match)
 		return -ENODEV;
 	}
 
-	while ((np = of_get_next_child(dev->ofdev.dev.of_node, np))) {
+	for_each_child_of_node(dev->ofdev.dev.of_node, np) {
 		if (of_device_is_compatible(np, "i2sbus") ||
 		    of_device_is_compatible(np, "i2s-modem")) {
 			got += i2sbus_add_dev(dev, control, np);