netdev/phy: skip disabled mdio-mux nodes

The mdio-mux driver scans all child mdio nodes, without regard to whether
the node is actually used. Some device trees include all possible
mdio-mux nodes and rely on the boot loader to disable those that are not
present, based on some run-time configuration. Those nodes need to be
skipped.

Signed-off-by: Timur Tabi <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/phy/mdio-mux.c

···
 	pb->mii_bus = parent_bus;
 
 	ret_val = -ENODEV;
-	for_each_child_of_node(dev->of_node, child_bus_node) {
+	for_each_available_child_of_node(dev->of_node, child_bus_node) {
 		u32 v;
 
 		r = of_property_read_u32(child_bus_node, "reg", &v);