arm64: dts: ti: k3-am65-mcu: Reserve some MCU SRAM for MCU R5F0

Add a child SRAM node to reserve a portion of the MCU domain on-chip
SRAM memory for use by the MCU domain R5F Core0. A preliminary size
of 256 KB (half of the current SRAM) is reserved to begin with and
can be adjusted as per need.

This memory is also added to the R5F0 remoteproc node using the
sram property.

Signed-off-by: Suman Anna <s-anna@ti.com>

arch/arm64/boot/dts/ti/k3-am65-mcu.dtsi

@@ -22,6 +22,10 @@
 		ranges = <0x0 0x00 0x41c00000 0x80000>;
 		#address-cells = <1>;
 		#size-cells = <1>;
+
+		mcu_r5fss0_core0_sram: r5f-sram@0 {
+			reg = <0x0 0x40000>;
+		};
 	};
 
 	mcu_i2c0: i2c@40b00000 {
@@ -131,6 +135,7 @@
 			btcm-enable = <1>;
 			loczrama = <1>;
 			mboxes = <&mailbox0_cluster0 &mbox_mcu_r5fss0_core0>;
+			sram = <&mcu_r5fss0_core0_sram>;
 		};
 
 		mcu_r5fss0_core1: r5f@41400000 {