net: dsa: microchip: ksz_common: Fix refcount leak bug

In ksz_switch_register(), we should call of_node_put() for the
reference returned by of_get_child_by_name() which has increased
the refcount.

Fixes: 912aae27 ("net: dsa: microchip: really look for phy-mode in port nodes")
Signed-off-by: Liang He <windhl@126.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20220714153138.375919-1-windhl@126.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/microchip/ksz_common.c

@@ -1038,18 +1038,21 @@ int ksz_switch_register(struct ksz_device *dev,
 		ports = of_get_child_by_name(dev->dev->of_node, "ethernet-ports");
 		if (!ports)
 			ports = of_get_child_by_name(dev->dev->of_node, "ports");
-		if (ports)
+		if (ports) {
 			for_each_available_child_of_node(ports, port) {
 				if (of_property_read_u32(port, "reg",
 							 &port_num))
 					continue;
 				if (!(dev->port_mask & BIT(port_num))) {
 					of_node_put(port);
+					of_node_put(ports);
 					return -EINVAL;
 				}
 				of_get_phy_mode(port,
 						&dev->ports[port_num].interface);
 			}
+			of_node_put(ports);
+		}
 		dev->synclko_125 = of_property_read_bool(dev->dev->of_node,
 							 "microchip,synclko-125");
 		dev->synclko_disable = of_property_read_bool(dev->dev->of_node,