dt-bindings: usb: ingenic,musb: Add usb-role-switch property

Add the common usb-role-switch boolean property to the list of the
supported properties.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/usb/ingenic,musb.yaml

@@ -42,6 +42,9 @@ properties:
   phys:
     description: PHY specifier for the USB PHY
 
+  usb-role-switch:
+    type: boolean
+
 required:
   - compatible
   - reg