net: phy: aquantia: add suspend / resume callbacks for AQR107 family

Add suspend / resume callbacks for AQR107 family. Suspend powers down
the complete chip except MDIO and internal CPU.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>