devm_mdiobus_alloc is already used. Be consistent and use
devm_of_mdiobus_register.
Also add a missing of_node_put for the mdio node.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/22998
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>