mdio_device_create() never returns NULL, thus checking for it in
of_mdiobus_register_device() is pointless...
Suggested-by: NVladimir Zapolskiy <vz@mleia.com>
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>