Add conditional dependency on kmod-of-mdio due to mdio_devres.c code:
#if IS_ENABLED(CONFIG_OF_MDIO)
...
EXPORT_SYMBOL(devm_of_mdiobus_register);
#endif /* CONFIG_OF_MDIO */
Fixes: 95a3741d17 ("kernel: support new mdio_devres.ko module in 5.10")
Reported-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Tony Ambardar <itugrok@yahoo.com>