ARM: dts: keystone-k2hk: Reserve MSM RAM for boot monitor

The Keystone 2 boot monitor uses 32 KB of the MSM RAM @ 0x0c5f0000
on 66AK2H SoCs, so add a reserved child node for the same.

This address is aligned to the values used within the latest boot
monitor firmware [1] as of commit cf8b431e8b3b ("soc: Move load
address to end of MSMC").

[1] git://git.ti.com/processor-firmware/ks2-boot-monitor.gitSigned-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Santosh Shilimkar <ssantosh@kernel.org>

arch/arm/boot/dts/keystone-k2hk.dtsi

@@ -52,6 +52,10 @@ msm_ram: msmram@0c000000 {
 			ranges = <0x0 0x0c000000 0x600000>;
 			#address-cells = <1>;
 			#size-cells = <1>;
+
+			sram-bm@5f0000 {
+				reg = <0x5f0000 0x8000>;
+			};
 		};
 
 		dspgpio0: keystone_dsp_gpio@02620240 {