ARM: dts: sun7i: Add Itead Ibox support

The Itead Ibox is a multi board device based on the Allwinner A20 SoC.
It contains the A20 Itead Core module and a base board for the external
interfaces.

The core module comes with 4GB NAND and 1GB DDR RAM.

The base board to which the core board is connected provides 3 USB 2.0 Host
ports, 1 USB 2.0 OTG, 1 uSD slot, 10/100 Ethernet port, HDMI, IR receiver,
SPDIF and a 32-pin GPIO header. This header expands the features of core
board by exposing the VGA pins, audio In/Out pins, SATA, SPI, I2C, UARTS,
USB-OTG and power.

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