net: sun8i-emac: set mux and clock by driver data

Use driver data->variant information to select device specific
pin mux and phy clock settings.

Suggested by Jagan Teki

Reviewed-by: Jagan Teki <jagan@openedev.com>
Tested-by: Jagan Teki <jagan@openedev.com>
Signed-off-by: Lothar Felten <lothar.felten@gmail.com>