arm64: dts: mediatek: add xHCI & usb phy for mt8173

add xHCI and phy drivers for MT8173-EVB

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>