Due to hardware design, we still need to set PHY address,
because MDIO controller of SP7021 only sends out MDIO 
commands with the same address listed in PHY address 
registers. The function below needs to be kept.

I suggest you actually set it to some other address. One of the
good/bad things about MDIO is you have no idea if the device is
there. A read to a device which does not exist just returns 0xffff,
not an error. So i would set the address of 0x1f. I've never seen a
PHY actually use that address.

    Andrew