dt-bindings: usb: mtk-xhci: add optional property to disable usb2 ports

Add support to disable specific usb2 host ports, it's useful when
a usb2 port is disabled on some platforms, but enabled on others for
the same SoC, another case is that the different package may support
different number of ports.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1629189389-18779-1-git-send-email-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml

@@ -152,6 +152,11 @@ properties:
     description: The mask to disable u3ports, bit0 for u3port0,
       bit1 for u3port1, ... etc
 
+  mediatek,u2p-dis-msk:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: The mask to disable u2ports, bit0 for u2port0,
+      bit1 for u2port1, ... etc
+
   "#address-cells":
     const: 1