ARM: dts: Add 128MiB OpenBMC flash layout

This is an alternate layout used by OpenBMC systems that require more
space on the BMC's flash. In addition to more space for the rootfs, it
supports a larger u-boot and Linux kernel FIT image.

The division of space is as follows:

 u-boot + env: 1MB
 kernel/FIT: 9MB
 rwfs: 86MB
 rofs: 32MB
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/boot/dts/openbmc-flash-layout-128.dtsi

+// SPDX-License-Identifier: GPL-2.0+
+
+partitions {
+	compatible = "fixed-partitions";
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	u-boot@0 {
+		reg = <0x0 0xe0000>; // 896KB
+		label = "u-boot";
+	};
+
+	u-boot-env@e0000 {
+		reg = <0xe0000 0x20000>; // 128KB
+		label = "u-boot-env";
+	};
+
+	kernel@100000 {
+		reg = <0x100000 0x900000>; // 9MB
+		label = "kernel";
+	};
+
+	rofs@a00000 {
+		reg = <0xa00000 0x5600000>; // 86MB
+		label = "rofs";
+	};
+
+	rwfs@6000000 {
+		reg = <0x6000000 0x2000000>; // 32MB
+		label = "rwfs";
+	};
+};