sunxi: dts: Add minimal dts files for board which lack a dts sofar

u-boot has support for a number of boards for which a dts file still needs
to be written, add minimal dts files for these boards so that we can switch
them over to driver-model / fdt.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Simon Glass <sjg@chromium.org>