doc: board: rockchip: Add missing supported boards

Update the list of supported boards with the information available
on doc/README.rockchip.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
1 file changed