sunxi: Add inet97fv2_defconfig

The inet97fv2 is a board found in the first generation of cheap allwinner
A10 based 7" tablets.

Note that this patch does not add a dts file as we already have one from
our dts syncs with the kernel.

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