ARM: dts: rainier: Add reserved memory for ramoops

Reserve a 1.5MiB region of memory to record kmsg dumps, console and
userspace message state into 16kiB ring-buffer slots. The sizing allows
for up to 16 dumps to be captured and read out.

Set max-reason to KMSG_DUMP_EMERG to capture bad-path reboots.

Signed-off-by: Andrew Jeffery <[e-mail]>
Reviewed-by: Joel Stanley <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Joel Stanley <[e-mail]>

arch/arm/boot/dts/aspeed-bmc-ibm-rainier.dts

···
 			reg = <0xB8000000 0x04000000>; /* 64M */
 		};
 
+		ramoops@bc000000 {
+			compatible = "ramoops";
+			reg = <0xbc000000 0x180000>; /* 16 * (3 * 0x8000) */
+			record-size = <0x8000>;
+			console-size = <0x8000>;
+			pmsg-size = <0x8000>;
+			max-reason = <3>; /* KMSG_DUMP_EMERG */
+		};
+
 		vga_memory: region@bf000000 {
 			no-map;
 			compatible = "shared-dma-pool";