dt-bindings: phy-rockchip-inno-usb2: add otg-mux interrupt

Add otg-mux property to support multiplexed interrupt in otg-port
on some Rockchip SoC (e.g RV1108).
Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/phy-rockchip-inno-usb2.txt

@@ -32,10 +32,14 @@ Required nodes : a sub-node is required for each port the phy provides.
 Required properties (port (child) node):
  - #phy-cells : must be 0. See ./phy-bindings.txt for details.
  - interrupts : specify an interrupt for each entry in interrupt-names.
- - interrupt-names : a list which shall be the following entries:
+ - interrupt-names : a list which should be one of the following cases:
+	Regular case:
 	* "otg-id" : for the otg id interrupt.
 	* "otg-bvalid" : for the otg vbus interrupt.
 	* "linestate" : for the host/otg linestate interrupt.
+	Some SoCs use one interrupt with the above muxed together, so for these
+	* "otg-mux" : otg-port interrupt, which mux otg-id/otg-bvalid/linestate
+		to one.
 
 Optional properties:
  - phy-supply : phandle to a regulator that provides power to VBUS.