dt-bindings: display: panel-simple: merge Innolux p120zdg-bf1

There is nothing special in Innolux p120zdg-bf1 panel, so just like
other Innolux panels it can be made part of panel-simple.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230326155425.91181-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Rob Herring <robh@kernel.org>