dt-bindings: usb: mtu3: 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.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1626340078-29111-3-git-send-email-chunfeng.yun@mediatek.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/mediatek,mtu3.yaml

@@ -166,6 +166,12 @@ properties:
     description: The mask to disable u3ports, bit0 for u3port0,
       bit1 for u3port1, ... etc
 
+  mediatek,u2p-dis-msk:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: The mask to disable u2ports, bit0 for u2port0,
+      bit1 for u2port1, ... etc; but can't disable u2port0 if dual role mode
+      is enabled, so will be skipped in this case.
+
 # Required child node when support dual-role
 patternProperties:
   "^usb@[0-9a-f]+$":