arm64: dts: ti: k3-am64-main: Reserve OCMRAM for DMSC-lite and secure proxy communication

The final 128KB in SRAM is reserved by default for DMSC-lite code and
secure proxy communication buffer. The memory region used for DMSC-lite
code can be optionally freed up by secure firmware API[1]. However, the
buffer for secure proxy communication is not configurable. This default
hardware configuration is unique for AM64.

Therefore, indicate the area reserved for DMSC-lite code and secure proxy
communication buffer in the oc_sram device tree node.

[1] - http://downloads.ti.com/tisci/esd/latest/6_topic_user_guides/security_handover.html#triggering-security-handover

Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Reviewed-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20210616171224.24635-3-a-govindraju@ti.com

arch/arm64/boot/dts/ti/k3-am64-main.dtsi

@@ -27,6 +27,14 @@
 		tfa-sram@0 {
 			reg = <0x0 0x20000>;
 		};
+
+		dmsc-sram@1e0000 {
+			reg = <0x1e0000 0x1c000>;
+		};
+
+		sproxy-sram@1fc000 {
+			reg = <0x1fc000 0x4000>;
+		};
 	};
 
 	main_conf: syscon@43000000 {