arm64: dts: allwinner: a64: Add SPDIF to the A64

Add the device tree sound bindings for the S/PDIF block.
Signed-off-by: Marcus Cooper <codekipper@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi

@@ -112,6 +112,24 @@ psci {
 		method = "smc";
 	};
 
+	sound_spdif {
+		compatible = "simple-audio-card";
+		simple-audio-card,name = "On-board SPDIF";
+
+		simple-audio-card,cpu {
+			sound-dai = <&spdif>;
+		};
+
+		simple-audio-card,codec {
+			sound-dai = <&spdif_out>;
+		};
+	};
+
+	spdif_out: spdif-out {
+		#sound-dai-cells = <0>;
+		compatible = "linux,spdif-dit";
+	};
+
 	timer {
 		compatible = "arm,armv8-timer";
 		interrupts = <GIC_PPI 13