ARM: sun6i: dt: Add new Mele I7 device

The Mele I7 is a Allwinner A31 based Android TV box, with 1G RAM,
8GB NAND flash, a RTL8188etv wifi chip, 3 USB Host ports using
USB-A receptacles, a micro USB-B receptacle for USB OTG, HDMI out,
a TRS connector for A/V, SPDIF and IrDA.

This patch adds basic support for the device, more information can
be found here (http://linux-sunxi.org/Mele_I7

).

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