net: davinci_emac: switch to new mdio

net: davinci_emac: switch to new mdio

This patch switches the emac implementation over to the newly separated
MDIO driver.

With this, the mdio bus frequency defaults to a safe 2.2MHz.  Boards may
optionally specify a bus frequency via platform data.

The phy identification scheme has been modified to use a phy bus id instead
of a mask.  This largely serves to eliminate the "phy search" code in emac
init.

Signed-off-by: Cyril Chemparathy <[email protected]>
Acked-by: David S. Miller <[email protected]>
Tested-by: Michael Williamson <[email protected]>
Tested-by: Caglar Akyuz <[email protected]>
Signed-off-by: Kevin Hilman <[email protected]>