arm64: dts: imx8dxl: Pass fsl,imx8dl-scu-pd

Pass 'fsl,imx8dl-scu-pd' to fix the following schema warning:

system-controller: power-controller:compatible:0: 'fsl,scu-pd' is not one of ['fsl,imx8qm-scu-pd', 'fsl,imx8qxp-scu-pd']
	from schema $id: http://devicetree.org/schemas/firmware/fsl,scu.yaml#Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8dxl.dtsi

@@ -122,7 +122,7 @@ &lsio_mu1 1 0
 			  &lsio_mu1 3 3>;
 
 		pd: power-controller {
-			compatible = "fsl,scu-pd";
+			compatible = "fsl,imx8dl-scu-pd", "fsl,scu-pd";
 			#power-domain-cells = <1>;
 			wakeup-irq = <160 163 235 236 237 228 229 230 231 238
 				     239 240 166 169>;