dt-bindings: mediatek: add compatible for MT8195 pwrap

This adds dt-binding documentation of pwrap for Mediatek MT8195
SoCs Platform.

Signed-off-by: Henry Chen <henryc.chen@mediatek.com>
Link: https://lore.kernel.org/r/20210602112050.12338-2-james.lo@mediatek.com


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