net: mdio: improve reset handling in mdio_device.c

net: mdio: improve reset handling in mdio_device.c

Change fwnode_property_read_u32() in mdio_device_register_reset()
to device_property_read_u32(), which is more appropriate here.

Make mdio_device_unregister_reset() truly reverse
mdio_device_register_reset() by setting the internal fields to
their default values.

Signed-off-by: Buday Csaba <buday.csaba@prolan.hu>
Link: https://patch.msgid.link/641df1488517ae71ba10158ec1e38424211d8651.1763473655.git.buday.csaba@prolan.hu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>