arm64: dts: renesas: Remove empty rgb output endpoints

Endpoints node must have a remote-endpoint property, as endpoints only
exist to model a link between ports. Drop the empty rgb output endpoints
from SoC dtsi files, and declare them in the board dts instead.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20220424161228.8147-2-laurent.pinchart+renesas@ideasonboard.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>