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

Add EE and AO domains pins for the spdif output to the gxl 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-gxl.dtsi

@@ -175,6 +175,20 @@ 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_9_pins: spdif_out_ao_9 {
+			mux {
+				groups = "spdif_out_ao_9";
+				function = "spdif_out_ao";
+			};
+		};
 	};
 };
 
@@ -449,6 +463,13 @@ mux {
 				function = "i2s_out";
 			};
 		};
+
+		spdif_out_h_pins: spdif_out_ao_h {
+			mux {
+				groups = "spdif_out_h";
+				function = "spdif_out";
+			};
+		};
 	};
 
 	eth-phy-mux {