macintosh: Switch to use for_each_child_of_node() macro

Use for_each_child_of_node() macro instead of open coding it.
No functional change.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220916141638.685575-1-yangyingliang@huawei.com

drivers/macintosh/windfarm_smu_controls.c

@@ -266,12 +266,11 @@ static int __init smu_controls_init(void)
 		return -ENODEV;
 
 	/* Look for RPM fans */
-	for (fans = NULL; (fans = of_get_next_child(smu, fans)) != NULL;)
+	for_each_child_of_node(smu, fans)
 		if (of_node_name_eq(fans, "rpm-fans") ||
 		    of_device_is_compatible(fans, "smu-rpm-fans"))
 			break;
-	for (fan = NULL;
-	     fans && (fan = of_get_next_child(fans, fan)) != NULL;) {
+	for_each_child_of_node(fans, fan) {
 		struct smu_fan_control *fct;
 
 		fct = smu_fan_create(fan, 0);
@@ -286,11 +285,10 @@ static int __init smu_controls_init(void)
 
 
 	/* Look for PWM fans */
-	for (fans = NULL; (fans = of_get_next_child(smu, fans)) != NULL;)
+	for_each_child_of_node(smu, fans)
 		if (of_node_name_eq(fans, "pwm-fans"))
 			break;
-	for (fan = NULL;
-	     fans && (fan = of_get_next_child(fans, fan)) != NULL;) {
+	for_each_child_of_node(fans, fan) {
 		struct smu_fan_control *fct;
 
 		fct = smu_fan_create(fan, 1);