sunxi: Add basic H3 support

Add initial sun8i H3 support, only uart + mmc are supported for now.

Signed-off-by: Jens Kuske <jenskuske@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>