dt-bindings: usb: mediatek,mtk-xhci: Add port for SuperSpeed EP

Add a port used to connect the SuperSpeed output endpoint to a
Type-C connector.

Note that the MediaTek XHCI controllers are always in front of a
different controller handling the USB HS (usually, MTU3), so the
only port that this controller provides is SuperSpeed, while the
HighSpeed one comes from elsewhere.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250220105514.43107-2-angelogioacchino.delregno@collabora.com


Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>