ARM: dts: Add Facebook BMC flash layout

This is the layout used by Facebook BMC systems. It describes the fixed
flash layout of a 32MB mtd device.
Signed-off-by: Tao Ren <taoren@fb.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/boot/dts/facebook-bmc-flash-layout.dtsi

+// SPDX-License-Identifier: GPL-2.0+
+// Copyright (c) 2018 Facebook Inc.
+
+partitions {
+	compatible = "fixed-partitions";
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	u-boot@0 {
+		reg = <0x0 0x60000>;
+		label = "u-boot";
+	};
+
+	u-boot-env@60000 {
+		reg = <0x60000 0x20000>;
+		label = "env";
+	};
+
+	fit@80000 {
+		reg = <0x80000 0x1b80000>;
+		label = "fit";
+	};
+
+	/*
+	 * "data0" partition is used by several Facebook BMC platforms
+	 * as persistent data store.
+	 */
+	data0@1c00000 {
+		reg = <0x1c00000 0x400000>;
+		label = "data0";
+	};
+
+	/*
+	 * Although the master partition can be created by enabling
+	 * MTD_PARTITIONED_MASTER option, below "flash0" partition is
+	 * explicitly created to avoid breaking legacy applications.
+	 */
+	flash0@0 {
+		reg = <0x0 0x2000000>;
+		label = "flash0";
+	};
+};