ARM: tegra: Add HDMI audio graph to Tegra20 device-tree

Add HDMI audio graph to Tegra20 device-tree to enable HDMI audio on
Tegra20 devices.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra20.dtsi

@@ -178,7 +178,7 @@ rgb {
 			};
 		};
 
-		hdmi@54280000 {
+		tegra_hdmi: hdmi@54280000 {
 			compatible = "nvidia,tegra20-hdmi";
 			reg = <0x54280000 0x00040000>;
 			interrupts = <GIC_SPI 75 IRQ_TYPE_LEVEL_HIGH>;
@@ -1040,4 +1040,24 @@ pmu {
 		interrupt-affinity = <&{/cpus/cpu@0}>,
 				     <&{/cpus/cpu@1}>;
 	};
+
+	sound-hdmi {
+		compatible = "simple-audio-card";
+		simple-audio-card,name = "NVIDIA Tegra20 HDMI";
+
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		simple-audio-card,dai-link@0 {
+			reg = <0>;
+
+			cpu {
+				sound-dai = <&tegra_spdif>;
+			};
+
+			codec {
+				sound-dai = <&tegra_hdmi>;
+			};
+		};
+	};
 };