net: phy: avoid genphy_aneg_done() for PHYs without clause 22 support

Avoid calling genphy_aneg_done() for PHYs that do not implement the
Clause 22 register set.

Clause 45 PHYs may implement the Clause 22 register set along with the
Clause 22 extension MMD.  Hence, we can't simply block access to the
Clause 22 functions based on the PHY being a Clause 45 PHY.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>