dt-bindings: mediatek: add compatible for MT8186 pwrap

This adds dt-binding documentation of pwrap for Mediatek MT8186
SoCs Platform.
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: NAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: NJohnson Wang <johnson.wang@mediatek.com>
Link: https://lore.kernel.org/r/20220207083034.15327-3-johnson.wang@mediatek.comSigned-off-by: NMatthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/soc/mediatek/pwrap.txt

@@ -27,6 +27,7 @@ Required properties in pwrap device node.
 	"mediatek,mt8135-pwrap" for MT8135 SoCs
 	"mediatek,mt8173-pwrap" for MT8173 SoCs
 	"mediatek,mt8183-pwrap" for MT8183 SoCs
+	"mediatek,mt8186-pwrap" for MT8186 SoCs
 	"mediatek,mt8195-pwrap" for MT8195 SoCs
 	"mediatek,mt8516-pwrap" for MT8516 SoCs
 - interrupts: IRQ for pwrap in SOC