arm64: dts: s32g: add SCMI firmware node

Linux controls the clocks over SCMI on S32G SoCs. Therefore,
add the SCMI device tree node and the reserved region for SCMI
messages.
Signed-off-by: Catalin Udma <catalin-dan.udma@nxp.com>
Signed-off-by: Ghennadi Procopciuc <ghennadi.procopciuc@nxp.com>
Reviewed-by: Matthias Brugger <mbrugger@suse.com>
Reviewed-by: Chester Lin <chester62515@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/s32g2.dtsi

@@ -3,7 +3,7 @@
  * NXP S32G2 SoC family
  *
  * Copyright (c) 2021 SUSE LLC
- * Copyright (c) 2017-2021 NXP
+ * Copyright 2017-2021, 2024 NXP
  */
 
 #include <dt-bindings/interrupt-controller/arm-gic.h>
@@ -14,6 +14,18 @@ / {
 	#address-cells = <2>;
 	#size-cells = <2>;
 
+	reserved-memory  {
+		#address-cells = <2>;
+		#size-cells = <2>;
+		ranges;
+
+		scmi_buf: shm@d0000000 {
+			compatible = "arm,scmi-shmem";
+			reg = <0x0 0xd0000000 0x0 0x80>;
+			no-map;
+		};
+	};
+
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
@@ -77,6 +89,19 @@ timer {
 	};
 
 	firmware {
+		scmi {
+			compatible = "arm,scmi-smc";
+			arm,smc-id = <0xc20000fe>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			shmem = <&scmi_buf>;
+
+			clks: protocol@14 {
+				reg = <0x14>;
+				#clock-cells = <1>;
+			};
+		};
+
 		psci {
 			compatible = "arm,psci-1.0";
 			method = "smc";