ARM: dts: sun7i: Add dts file for the Orangepi mini SBC

ARM: dts: sun7i: Add dts file for the Orangepi mini SBC

The Orangepi mini is a development board using the Allwinner A20 SoC,
with 1G RAM, 2 microsd slots (use the top side one for booting), HDMI,
1Gbit ethernet, USB wifi, Micro USB (otg), sata, 4 USB A ports,
ir receiver and a headphones jack.

Also see:
http://linux-sunxi.org/Xunlong_Orange_Pi_Mini
http://www.orangepi.org/

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[maxime: Added /chosen/stdout-path]
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>