net: phy: mdio-mvusb: select MDIO_DEVRES in Kconfig

PHYLIB is not selected by the mvusb driver but it uses mdio devres
helpers. Explicitly select MDIO_DEVRES in this driver's Kconfig entry.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 1814cff2 ("net: phy: add a Kconfig option for mdio_devres")
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>