Originally was in the panel-simple, but belongs to panel-simple-dsi.

See arch/arm/boot/dts/nvidia/tegra114-roth.dts for more details.

Resolves the following warning:
```
arch/arm/boot/dts/tegra114-roth.dt.yaml: panel@0: 'reg' does not match any of the regexes: 'pinctrl-[0-9]+'
        From schema: Documentation/devicetree/bindings/display/panel/panel-simple.yaml
```

Fixes: 310abcea ("dt-bindings: display: convert simple lg panels to DT Schema")
Signed-off-by: David Heidelberg <david@ixit.cz>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Link: https://lore.kernel.org/r/20231212200934.99262-1-david@ixit.czSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231212200934.99262-1-david@ixit.cz