ARM: dts: keystone-k2l: Reserve MSM RAM for boot monitor

The Keystone 2 boot monitor uses 32 KB of the MSM RAM @ 0x0c1f8000
on 66AK2L 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: NSuman Anna <s-anna@ti.com>
Signed-off-by: NSantosh Shilimkar <ssantosh@kernel.org>

arch/arm/boot/dts/keystone-k2l.dtsi

@@ -210,6 +210,10 @@
 			ranges = <0x0 0x0c000000 0x200000>;
 			#address-cells = <1>;
 			#size-cells = <1>;
+
+			sram-bm@1f8000 {
+				reg = <0x001f8000 0x8000>;
+			};
 		};
 
 		dspgpio0: keystone_dsp_gpio@02620240 {