net: phy: at803x: add support for AR8032 PHY

This adds support for the Qualcomm Atheros AR8032 Fast Ethernet PHY.

It shares many similarities with the already supported AR8030 PHY but
additionally supports MII connection to the MAC.

Signed-off-by: David Bauer <mail@david-bauer.net>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>