arm64: dts: imx93: add s4 mu node

Add s4 mu node for sentinel communication
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx93.dtsi

@@ -342,5 +342,14 @@ gpio1: gpio@47400080 {
 			clock-names = "gpio", "port";
 			gpio-ranges = <&iomuxc 0 0 32>;
 		};
+
+		s4muap: mailbox@47520000 {
+			compatible = "fsl,imx93-mu-s4";
+			reg = <0x47520000 0x10000>;
+			interrupts = <GIC_SPI 31 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 30 IRQ_TYPE_LEVEL_HIGH>;
+			interrupt-names = "txirq", "rxirq";
+			#mbox-cells = <2>;
+		};
 	};
 };