arm64: dts: imx: add i.MX8QXP system controller RTC support

Add i.MX8QXP system controller RTC support.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8qxp.dtsi

@@ -112,6 +112,10 @@ pd: imx8qx-pd {
 			compatible = "fsl,imx8qxp-scu-pd";
 			#power-domain-cells = <1>;
 		};
+
+		rtc: rtc {
+			compatible = "fsl,imx8qxp-sc-rtc";
+		};
 	};
 
 	timer {