arm64: dts: ti: k3-am65-mcu: Add the MCU RAM node

Add the on-chip SRAM present within the MCU domain as a mmio-sram node.
The K3 AM65x SoCs have 512 KB of such memory. Any specific memory range
within this RAM needed by a 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-am65-mcu.dtsi

@@ -17,6 +17,14 @@ mcu_uart0: serial@40a00000 {
 			power-domains = <&k3_pds 149>;
 	};
 
+	mcu_ram: sram@41c00000 {
+		compatible = "mmio-sram";
+		reg = <0x00 0x41c00000 0x00 0x80000>;
+		ranges = <0x0 0x00 0x41c00000 0x80000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+	};
+
 	mcu_i2c0: i2c@40b00000 {
 		compatible = "ti,am654-i2c", "ti,omap4-i2c";
 		reg = <0x0 0x40b00000 0x0 0x100>;