arm64: dts: imx8-ss-dma: Move dma_ipg_clk outside of soc

The dma_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-dma.dtsi

@@ -7,19 +7,19 @@
 #include <dt-bindings/clock/imx8-lpcg.h>
 #include <dt-bindings/firmware/imx/rsrc.h>
 
+dma_ipg_clk: clock-dma-ipg {
+	compatible = "fixed-clock";
+	#clock-cells = <0>;
+	clock-frequency = <120000000>;
+	clock-output-names = "dma_ipg_clk";
+};
+
 dma_subsys: bus@5a000000 {
 	compatible = "simple-bus";
 	#address-cells = <1>;
 	#size-cells = <1>;
 	ranges = <0x5a000000 0x0 0x5a000000 0x1000000>;
 
-	dma_ipg_clk: clock-dma-ipg {
-		compatible = "fixed-clock";
-		#clock-cells = <0>;
-		clock-frequency = <120000000>;
-		clock-output-names = "dma_ipg_clk";
-	};
-
 	lpspi0: spi@5a000000 {
 		compatible = "fsl,imx7ulp-spi";
 		reg = <0x5a000000 0x10000>;