net: phy: add "has_fixups" boolean property

Add a boolean property which indicates if the PHY has had any fixup
routine ran on it. We are later going to use that boolean to expose it
as a sysfs property to help troubleshooting.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>