net-next: phy: new Asix Electronics PHY driver

The Asix Electronics PHY found on the X-Surf 100 Amiga Zorro network
card by Individual Computers is buggy, and needs the reset bit toggled
as workaround to make a PHY soft reset succeed.

Add workaround driver just for this special case.

Suggested in xsurf100 patch series review by Andrew Lunn <andrew@lunn.ch>

Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>