sun7i: Add defconfig for the Itead Ibox

Add defconfig for the 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>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>