hwmon: (pmbus/isl68137) Fix child node reference leak on early return

In the case of an early return, the reference to the child node needs
to be released.

Use for_each_child_of_node_scoped to fix the issue.

Fixes: 3996187f80a0e ("hwmon: (pmbus/isl68137) add support for voltage divider on Vout")
Signed-off-by: Erick Karanja <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
[groeck: Updated subject/description]
Signed-off-by: Guenter Roeck <[e-mail]>

drivers/hwmon/pmbus/isl68137.c

···
 				  struct isl68137_data *data)
 {
 	const struct device_node *np = dev->of_node;
-	struct device_node *child;
 	int err;
 
-	for_each_child_of_node(np, child) {
+	for_each_child_of_node_scoped(np, child) {
 		if (strcmp(child->name, "channel"))
 			continue;