staging: octeon: Use 'for_each_child_of_node'

Use 'for_each_child_of_node' instead of hand writing it.
This saves a few line of code.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/eaffe388e6c51e97caf3e8fa474de74428575455.1618920182.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/octeon/ethernet.c

@@ -614,14 +614,11 @@ static const struct net_device_ops cvm_oct_pow_netdev_ops = {
 static struct device_node *cvm_oct_of_get_child
 				(const struct device_node *parent, int reg_val)
 {
-	struct device_node *node = NULL;
-	int size;
+	struct device_node *node;
 	const __be32 *addr;
+	int size;
 
-	for (;;) {
-		node = of_get_next_child(parent, node);
-		if (!node)
-			break;
+	for_each_child_of_node(parent, node) {
 		addr = of_get_property(node, "reg", &size);
 		if (addr && (be32_to_cpu(*addr) == reg_val))
 			break;