dt-bindings: display: drop minItems equal to maxItems

dt-bindings: display: drop minItems equal to maxItems

minItems, if missing, are implicitly equal to maxItems, so drop
redundant piece to reduce size of code.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20220825113334.196908-5-krzysztof.kozlowski@linaro.org
Signed-off-by: Rob Herring <robh@kernel.org>