sunxi: Add mk802_a10s board / defconfig

The mk802_a10s re-uses is the "classic" mk802 case and functionality, but has
an A10s SoC inside rather then the A10, it features 512M or 1G RAM, 4G nand,
a mini-hdmi female connector, USB-A receptacle, mini-usb receptacle (OTG)
and a sdio realtek wifi chip. Unlike the original mk802 it does have a pmic,
the axp152.

For more details see: http://linux-sunxi.org/Semitime_g2



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