drivers/macintosh/smu.c: use for_each_child_of_node() macro

Use for_each_child_of_node() macro instead of open coding it.
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200916062122.190586-1-miaoqinglang@huawei.com

drivers/macintosh/smu.c

@@ -638,7 +638,7 @@ static void smu_expose_childs(struct work_struct *unused)
 {
 	struct device_node *np;
 
-	for (np = NULL; (np = of_get_next_child(smu->of_node, np)) != NULL;)
+	for_each_child_of_node(smu->of_node, np)
 		if (of_device_is_compatible(np, "smu-sensors"))
 			of_platform_device_create(np, "smu-sensors",
 						  &smu->of_dev->dev);