dt-bindings: display: add #sound-dai-cells property to rockchip rk3066 hdmi

The Rockchip rk3066 HDMI controller can take one I2S input and transmit it
over the HDMI output. Add #sound-dai-cells (= 0) to the binding for it.
Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/b9864655-7c60-4066-8305-f291a3551872@gmail.com

Documentation/devicetree/bindings/display/rockchip/rockchip,rk3066-hdmi.yaml

@@ -10,6 +10,9 @@ maintainers:
   - Sandy Huang <hjc@rock-chips.com>
   - Heiko Stuebner <heiko@sntech.de>
 
+allOf:
+  - $ref: /schemas/sound/dai-common.yaml#
+
 properties:
   compatible:
     const: rockchip,rk3066-hdmi
@@ -34,6 +37,9 @@ properties:
     description:
       This soc uses GRF regs to switch the HDMI TX input between vop0 and vop1.
 
+  "#sound-dai-cells":
+    const: 0
+
   ports:
     $ref: /schemas/graph.yaml#/properties/ports
 
@@ -83,6 +89,7 @@ examples:
       pinctrl-names = "default";
       power-domains = <&power RK3066_PD_VIO>;
       rockchip,grf = <&grf>;
+      #sound-dai-cells = <0>;
 
       ports {
         #address-cells = <1>;