GPHY Autopowerdown (APD) is a way to save power when energy is not
detected on the wire.  At the moment, only the 5784 and 5761 are
capable of enabling this mode.
Signed-off-by: NMatt Carlson <mcarlson@broadcom.com>
Signed-off-by: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>