sunxi: Add defconfig 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.

The dts changes are identical to the dts files submitted upstream.

A few notes on the use if dldo and aldo regulators. DLDO1 is used
for Vdd for the ethernet phy, ALDO2 is used for AVdd for the ethernet
phy. ALDO1 is used to power the sdio wifi module.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>