dt-bindings: display: bridge: renesas,dsi: allow properties from dsi-controller

dt-bindings: display: bridge: renesas,dsi: allow properties from dsi-controller

Allow to inherit valid properties from the dsi-controller. This fixes the
following warning when adding a panel property:

rzg2lc.dtb: dsi@10850000: '#address-cells', '#size-cells', 'panel@0' do not
    match any of the regexes: 'pinctrl-[0-9]+'
    from schema $id:
        http://devicetree.org/schemas/display/bridge/renesas,dsi.yaml#

Also add a panel property to the example.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250520151112.3278569-1-hugo@hugovil.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>