arm64: dts: imx8-ss-audio: Move audio_ipg_clk outside of soc

The audio_ipg_clk node does not have any register associated with it,
so it should be moved outside of soc to fix schema warning from
simple-bus.yaml.
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8-ss-audio.dtsi

@@ -7,19 +7,19 @@
 #include <dt-bindings/clock/imx8-lpcg.h>
 #include <dt-bindings/firmware/imx/rsrc.h>
 
+audio_ipg_clk: clock-audio-ipg {
+	compatible = "fixed-clock";
+	#clock-cells = <0>;
+	clock-frequency = <120000000>;
+	clock-output-names = "audio_ipg_clk";
+};
+
 audio_subsys: bus@59000000 {
 	compatible = "simple-bus";
 	#address-cells = <1>;
 	#size-cells = <1>;
 	ranges = <0x59000000 0x0 0x59000000 0x1000000>;
 
-	audio_ipg_clk: clock-audio-ipg {
-		compatible = "fixed-clock";
-		#clock-cells = <0>;
-		clock-frequency = <120000000>;
-		clock-output-names = "audio_ipg_clk";
-	};
-
 	dsp_lpcg: clock-controller@59580000 {
 		compatible = "fsl,imx8qxp-lpcg";
 		reg = <0x59580000 0x10000>;