dt-bindings: arm64: dts: mediatek: Add mt8192-asurada-spherion

Add binding for the Google Spherion board, which is used for Acer
Chromebook 514 (CB514-2H).
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220629155956.1138955-2-nfraprado@collabora.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/arm/mediatek.yaml

@@ -131,6 +131,14 @@ properties:
           - enum:
               - mediatek,mt8183-evb
           - const: mediatek,mt8183
+      - description: Google Spherion (Acer Chromebook 514)
+        items:
+          - const: google,spherion-rev3
+          - const: google,spherion-rev2
+          - const: google,spherion-rev1
+          - const: google,spherion-rev0
+          - const: google,spherion
+          - const: mediatek,mt8192
       - items:
           - enum:
               - mediatek,mt8186-evb