net: phy: allow settings table to support more than 32 link modes

Allow the phy settings table to support more than 32 link modes by
switching to the ethtool link mode bit number representation, rather
than storing the mask.  This will allow phylink and other ethtool
code to share the settings table to look up settings.

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