ARM: dts: sun6i: Add a dts file for the Sinovoip BPI-M2 board

The Sinovoip BPI-M2 is a SBC board based on the A31s SoC it features
1G RAM, a microsd slot, Gbit ethernet, 4 usb-a USB-2 ports, ir receiver,
stereo headphone jack and hdmi video output.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>