dt-bindings: usb: mediatek,mtk-xhci: add MT8365 SoC bindings

Add binding documentation for the MT8365 SoC.

Signed-off-by: Fabien Parent <fparent@baylibre.com>
[bero@baylibre.com: Cleanups suggested by reviewers]
Signed-off-by: Bernhard Rosenkränzer <bero@baylibre.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20230125143503.1015424-7-bero@baylibre.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>