MIPS: mscc: Add ocelot PCB123 device tree

Add a device tree for the Microsemi Ocelot PCB123 evaluation board.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Allan Nielsen <Allan.Nielsen@microsemi.com>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/18856/Signed-off-by: James Hogan <jhogan@kernel.org>

arch/mips/boot/dts/mscc/Makefile

+dtb-$(CONFIG_LEGACY_BOARD_OCELOT)	+= ocelot_pcb123.dtb
+
 obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))

arch/mips/boot/dts/mscc/ocelot_pcb123.dts

+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Copyright (c) 2017 Microsemi Corporation */
+
+/dts-v1/;
+
+#include "ocelot.dtsi"
+
+/ {
+	compatible = "mscc,ocelot-pcb123", "mscc,ocelot";
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0x0 0x0e000000>;
+	};
+};
+
+&uart0 {
+	status = "okay";
+};
+
+&uart2 {
+	status = "okay";
+};