net:ethernet:aquantia: Add 2500/5000 mbit link modes support.

Using new link mode indices instead deprecated SUPPORTED_/ADVERTISED_
macro.

Added indication for 2500 and 5000mbit link modes (AQtion adapter already
supports these speeds).

Signed-off-by: Pavel Belous <pavel.belous@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>