arm64: dts: exynos: Add reserved memory for pstore on E850-96

Reserve a 2 MiB memory region to record kmsg dumps, console, ftrace and
userspace messages. The implemented memory split allows capturing and
reading corresponding ring buffers:
  * dmesg: 6 dumps, 128 KiB each
  * console: 128 KiB
  * ftrace: 128 KiB for each of 8 CPUs (1 MiB total)
  * userspace messages: 128 KiB

Signed-off-by: Sam Protsenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[krzysztof: move the node to alphabetically sorted position]
Signed-off-by: Krzysztof Kozlowski <[email protected]>

Author: Sam Protsenko

arch/arm64/boot/dts/exynos/exynos850-e850-96.dts

@@ -141,6 +141,21 @@
 		gpio = <&gpa3 5 GPIO_ACTIVE_LOW>;
 	};
 
+	reserved-memory {
+		#address-cells = <2>;
+		#size-cells = <1>;
+		ranges;
+
+		ramoops@f0000000 {
+			compatible = "ramoops";
+			reg = <0x0 0xf0000000 0x200000>;
+			record-size = <0x20000>;
+			console-size = <0x20000>;
+			ftrace-size = <0x100000>;
+			pmsg-size = <0x20000>;
+		};
+	};
+
 	/*
 	 * RTC clock (XrtcXTI); external, must be 32.768 kHz.
 	 *