phylink: ensure AN is enabled

Ensure that we mark AN as enabled at boot time, rather than leaving
it disabled.  This is noticable if your SFP module is fiber, and
it supports faster speeds than 1G with 2.5G support in place.

Fixes: 9525ae83

 ("phylink: add phylink infrastructure")
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>