arm64: dts: ti: k3-j721e: Add the MCU SRAM node

Add the on-chip SRAM present within the MCU domain as a mmio-sram node.
The K3 J721E SoCs have 1 MB of such memory. Any specific memory range
within this RAM needed by a driver/software module ought to be reserved
using an appropriate child node.
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>

arch/arm64/boot/dts/ti/k3-j721e-mcu-wakeup.dtsi

@@ -43,6 +43,14 @@ wkup_pmx0: pinmux@4301c000 {
 		pinctrl-single,function-mask = <0xffffffff>;
 	};
 
+	mcu_ram: sram@41c00000 {
+		compatible = "mmio-sram";
+		reg = <0x00 0x41c00000 0x00 0x100000>;
+		ranges = <0x0 0x00 0x41c00000 0x100000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+	};
+
 	wkup_uart0: serial@42300000 {
 		compatible = "ti,j721e-uart", "ti,am654-uart";
 		reg = <0x00 0x42300000 0x00 0x100>;