net: phy: add driver for aquantia phy

This patch added driver to support Aquantia PHYs AQ1202, AQ2104, AQR105,
AQR405, which accessed through clause 45.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>