ARM64: dts: meson-gxbb: add spdif output pins

Add EE and AO domains pins for the spdif output to the gxbb device tree.
Acked-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi

@@ -235,6 +235,20 @@ mux {
 				function = "i2s_out_ao";
 			};
 		};
+
+		spdif_out_ao_6_pins: spdif_out_ao_6 {
+			mux {
+				groups = "spdif_out_ao_6";
+				function = "spdif_out_ao";
+			};
+		};
+
+		spdif_out_ao_13_pins: spdif_out_ao_13 {
+			mux {
+				groups = "spdif_out_ao_13";
+				function = "spdif_out_ao";
+			};
+		};
 	};
 };
 
@@ -497,6 +511,13 @@ mux {
 				function = "i2s_out";
 			};
 		};
+
+		spdif_out_y_pins: spdif_out_y {
+			mux {
+				groups = "spdif_out_y";
+				function = "spdif_out";
+			};
+		};
 	};
 };