The port's PHY and MAC are both implied in EEE. The current code does
not call the PHY operations if the related device is NULL. Change that
by returning -ENODEV if there's no PHY device attached to the interface.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>