dt-bindings: arm64: dts: mediatek: Add mt8167-pumpkin board

Add binding documentation for the MT8167 Pumpkin board.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201027194816.1227654-1-fparent@baylibre.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/arm/mediatek.yaml

@@ -84,6 +84,10 @@ properties:
           - enum:
               - mediatek,mt8135-evbp1
           - const: mediatek,mt8135
+      - items:
+          - enum:
+              - mediatek,mt8167-pumpkin
+          - const: mediatek,mt8167
       - description: Google Elm (Acer Chromebook R13)
         items:
           - const: google,elm-rev8