sun7i: Add support for the MK808C board

The MK808C is a Allwinner based Android TV dongle.

It features a A20 SOC, 1G RAM, 8GB NAND, HDMI out, A/V out,
1 USB A, 1 USB mini OTG, Bluetooth and Wireless LAN.

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>