ucc_geth: Add SUPPORTED_MII and SUPPORTED_Autoneg

The driver supports Autoneg and at least MII. Tell the PHY
that to avoid any confusion in the PHY code.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David S. Miller <davem@davemloft.net>