sunxi: Add defconfig and dts for Dserve DSRV9703C tablet

The Dserve DSRV9703C is a 9.7" A10 tablet with a 1024x768 ips LCD,
1G RAM, 4GB flash, a Focaltech FT5406EE8 touchscreen and rtl8188ctv wifi.

The dts file is identical to the one submitted to the upstream kernel.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>