dt-bindings: display: renesas: dw-hdmi: Tidyup example compatible

The DT example erronously uses the "renesas,r8a7795-dw-hdmi", when the
correct value is "renesas,r8a7795-hdmi". It is furthermore missing the
generic "renesas,rcar-gen3-hdmi" compatible string. Fix it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
[Add "renesas,rcar-gen3-hdmi" and rework commit message]
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Documentation/devicetree/bindings/display/bridge/renesas,dw-hdmi.txt

@@ -43,7 +43,7 @@ Optional properties:
 Example:
 
 	hdmi0: hdmi@fead0000 {
-		compatible = "renesas,r8a7795-dw-hdmi";
+		compatible = "renesas,r8a7795-hdmi", "renesas,rcar-gen3-hdmi";
 		reg = <0 0xfead0000 0 0x10000>;
 		interrupts = <0 389 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&cpg CPG_CORE R8A7795_CLK_S0D4>, <&cpg CPG_MOD 729>;