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.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>