dt-bindings: arm64: dts: mediatek: Add mt8195-demo board

Add bindings for the MediaTek mt8195-demo board.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220415150003.1793063-2-fparent@baylibre.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/arm/mediatek.yaml

@@ -137,6 +137,7 @@ properties:
           - const: mediatek,mt8192
       - items:
           - enum:
+              - mediatek,mt8195-demo
               - mediatek,mt8195-evb
           - const: mediatek,mt8195
       - description: Google Burnet (HP Chromebook x360 11MK G3 EE)