Split link_an_mode between the configured setting and the current
operating setting.  This is an important distinction to make when we
need to configure PHY mode for a plugged SFP+ module that does not
use in-band signalling.
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>