net: stmmac: sunxi platfrom extensions for GMAC in Allwinner A20 SoC's

The Allwinner A20 has an ethernet controller that seems to be
an early version of Synopsys DesignWare MAC 10/100/1000 Universal,
which is supported by the stmmac driver.

Allwinner's GMAC requires setting additional registers in the SoC's
clock control unit.

The exact version of the DWMAC IP that Allwinner uses is unknown,
thus the exact feature set is unknown.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: dts: sun7i: Add GMAC controller node to sun7i DTSI

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: dts: sun7i: Add pin muxing options for the GMAC

The A20 has EMAC and GMAC muxed on the same pins.
Add pin sets with gmac function for MII and RGMII mode to the DTSI.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: dts: sun7i: cubietruck: Enable the GMAC

The CubieTruck uses the GMAC with an RGMII phy.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: dts: sun7i: cubieboard2: Enable GMAC instead of EMAC

GMAC has better performance and fewer hardware issues.
Use the GMAC in MII mode for ethernet instead of the EMAC.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: dts: sun7i: olinuxino-micro: Enable GMAC instead of EMAC

GMAC has better performance and fewer hardware issues.
Use the GMAC in MII mode for ethernet instead of the EMAC.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: dts: sun7i: Add ethernet alias for GMAC

U-Boot will insert MAC address into the device tree image.
It looks up ethernet[0-5] aliases to find the ethernet nodes.
Alias GMAC as ethernet0, as it is the only ethernet controller used.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>