ARM: dts: sun8i: add FriendlyARM NanoPi Duo2

This is an Allwinner H3 based board, with 512MB ram, a USB OTG port,
microsd slot, an onboard AP6212A wifi/bluetooth module, and a CSI
connector.

Full details and schematic available from vendor:
http://wiki.friendlyarm.com/wiki/index.php/NanoPi_Duo2



Signed-off-by: Karl Palsson <karlp@tweak.net.au>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>