ARM: dts: sunxi: Add Allwinner A80 dtsi

The Allwinner A80 is a new multi-purpose SoC with 4 Cortex-A7 and
4 Cortex-A15 cores in a big.LITTLE architecture, and a 64-core
PowerVR G6230 GPU.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: dts: sun9i: Add A80 Optimus Board support

The A80 Optimus Board is was launched with the Allwinner A80 SoC.
It was jointly developed by Allwinner and Merrii.

This board has a UART port, a JTAG connector, USB host ports, a USB
3.0 OTG connector, an HDMI output, a micro SD slot, 8G NAND flash,
4G DRAM, a camera sensor interface, a WiFi/BT combo chip, a headphone
jack, IR receiver, and additional GPIO headers.

This patch adds only basic support.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
devicetree: bindings: Add vendor prefix for Merrii Technology Co., Ltd.

Merrii Technology Co., Ltd. is a Chinese ARM integration developer that
specializes in Allwinner SoC based designs.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
devicetree: bindings: Document supported Allwinner sunxi SoCs

This adds a list of supported Allwinner SoC bindings.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Documentation: sunxi: Add A80 datasheet link

We now have initial support for the A80, as well a the datasheet.
Update the documents to reflect this.

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