sunxi: Add defconfig and dts file for inet86dz board

The inet86dz board is a board used in 7" tablets from various oems.

These tablets are a23 based 7" tablets featuring a 1024x600 LCD,
512MB RAM, 4G NAND, rtl8188etv usb wifi, gsl1680 touchschreen,
micro-sd slot, 3.5mm headphone jack and a micro-usb otg connector
which doubles as charging port.

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

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