dt-bindings: mediatek: add compatible for MT8186 pwrap

This adds dt-binding documentation of pwrap for Mediatek MT8186
SoCs Platform.

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Johnson Wang <johnson.wang@mediatek.com>
Link: https://lore.kernel.org/r/20220207083034.15327-3-johnson.wang@mediatek.com


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