arm64: dts: renesas: ulcb: Merge hdmi0_con

arm64: dts: renesas: ulcb: Merge hdmi0_con

The remote endpoint for the hdmi connector is specfied through a
reference to the hdmi0_con endpoint, which is in the same file.

Simplify by specifying the remote-endpoint directly in the hdmi0_con
endpoint.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20211124152815.3926961-2-kieran.bingham+renesas@ideasonboard.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>