net: phy: use genphy_c45_aneg_done in genphy_aneg_done

Now that we have it let's use genphy_c45_aneg_done() in phy_aneg_done().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>