dt-bindings: pwm: Add compatible for MediaTek MT8186

Add dt-binding documentation of pwm for MediaTek MT8186 SoC.

Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

Author: panghu-xinlei

Documentation/devicetree/bindings/pwm/mediatek,pwm-disp.yaml

@@ -26,6 +26,7 @@ properties:
           - const: mediatek,mt8173-disp-pwm
       - items:
           - enum:
+              - mediatek,mt8186-disp-pwm
               - mediatek,mt8192-disp-pwm
               - mediatek,mt8195-disp-pwm
           - const: mediatek,mt8183-disp-pwm