Implements the phy tunable function pointers and implement downshift
functionality for MSCC PHYs.
Signed-off-by: NRaju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NAllan W. Nielsen <allan.nielsen@microsemi.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>