net: phy: improve phy_resolve_aneg_linkmode

We have the settings array of modes which is sorted based on aneg
priority. Instead of checking each mode manually let's simply iterate
over the sorted settings.

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