Add HDMI I2S config

From Sipeed, This should enable HDMI Audio

arch/riscv/boot/dts/thead/light-lpi4a-ref.dts

@@ -743,7 +743,7 @@
 	num-cs = <1>;
 	cs-gpios = <&gpio2_porta 3 0>;
 	rx-sample-dly = <4>;
-	status = "okay";
+	status = "disabled";
 
 	spi-flash@0 {
 		#address-cells = <1>;
@@ -1411,6 +1411,16 @@
                         sound-dai = <&es7210_audio_codec>;
                 };
         };
+        simple-audio-card,dai-link@2 {          /* I2S - HDMI */
+                reg = <2>;
+                format = "i2s";
+                cpu {
+                        sound-dai = <&light_i2s 1>;
+                };
+                codec {
+                        sound-dai = <&dummy_codec 2>;
+                };
+        };
 };
 
 &light_i2s {