The upcoming PCS driver will lookup the SerDes mdio bus via
of_mdio_find_bus() and the devicetree. This is only possible
with proper registration via devm_of_mdiobus_register().
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/20078
Signed-off-by: Robert Marko <robimarko@gmail.com>