dt-bindings: arm64: dts: mediatek: Add mt8516-pumpkin board

Add binding documentation for the MT8516 Pumpkin board.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210223223613.2085827-1-fparent@baylibre.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/arm/mediatek.yaml

@@ -138,6 +138,10 @@ properties:
           - const: google,juniper-sku16
           - const: google,juniper
           - const: mediatek,mt8183
+      - items:
+          - enum:
+              - mediatek,mt8516-pumpkin
+          - const: mediatek,mt8516
 
 additionalProperties: true