sun5i: Add defconfig and dts file for the Empire Electronix D709 tablet

sun5i: Add defconfig and dts file for the Empire Electronix D709 tablet

The Empire Electronix D709 tablet is a fairly standard 7" A13 tablet,
featuring usb-wifi, a micro-sd slot, micro-usb otg and headphone jack.

Empire Electronix is written on the back of the tablet, the D709 model
info can be found in the about tablet menu in android.

The PCB has no markings to speak of.

This dts file 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>