arm64: dts: rockchip: update mipi cells for RK3399

We might include additional ports in derivative device trees, so the
'port' node should have an address, and the parent 'ports' node needs
/#{addres,size}-cells.

Signed-off-by: Nickey Yang <nickey.yang@rock-chips.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>