net: Add EMAC ethernet driver found on Allwinner A10 SoC's

The Allwinner A10 has an ethernet controller that seem to be developped
internally by them.

The exact feature set of this controller is unknown, since there is no
public documentation for this IP, and this driver is mostly the one
published by Allwinner that has been heavily cleaned up.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
ARM: sunxi: Add EMAC controller node to sun4i DTSI

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
ARM: sun4i: Add muxing options for the ethernet controller

The EMAC only has one pinset available for muxing, so hopefully, we
cover all cases.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
ARM: cubieboard: Enable ethernet (WEMAC) support in dts

Signed-off-by: Stefan Roese <sr@denx.de>
ARM: hackberry: dt: Add Ethernet controller to the Hackberry device tree

The Hackberry has a PHY that needs to be powered up through a GPIO, so
we need to use a fixed regulator here.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>