dt-bindings: usb: mtk-xhci: add compatible for mt8186

Add compatible for mt8186

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Link: https://lore.kernel.org/r/20220216120025.29860-1-allen-kh.cheng@mediatek.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>