drm/rockchip: rgb: add video_port parameter to init function

The VOP2 driver has more than one video port, hence the hard-coded
port id will not work anymore. Add an extra parameter for the video
port id to the rockchip_rgb_init function.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230124054706.3921383-4-michael.riesch@wolfvision.net