arm64: dts: rockchip: fix rk3399 hdmi ports node

[ Upstream commit f051b6ac

 ]

Fix rk3399 hdmi ports node so that it matches the
rockchip,dw-hdmi.yaml binding.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/a6ab6f75-3b80-40b1-bd30-3113e14becdd@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>