arm64: dts: imx8-ss-img: Move img_ipg_clk outside of soc

The img_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-img.dtsi

@@ -3,19 +3,19 @@
  * Copyright 2019-2021 NXP
  * Zhou Guoniu <guoniu.zhou@nxp.com>
  */
+img_ipg_clk: clock-img-ipg {
+	compatible = "fixed-clock";
+	#clock-cells = <0>;
+	clock-frequency = <200000000>;
+	clock-output-names = "img_ipg_clk";
+};
+
 img_subsys: bus@58000000 {
 	compatible = "simple-bus";
 	#address-cells = <1>;
 	#size-cells = <1>;
 	ranges = <0x58000000 0x0 0x58000000 0x1000000>;
 
-	img_ipg_clk: clock-img-ipg {
-		compatible = "fixed-clock";
-		#clock-cells = <0>;
-		clock-frequency = <200000000>;
-		clock-output-names = "img_ipg_clk";
-	};
-
 	jpegdec: jpegdec@58400000 {
 		reg = <0x58400000 0x00050000>;
 		interrupts = <GIC_SPI 309 IRQ_TYPE_LEVEL_HIGH>;