MIPS: mscc: Add luton PC0B91 device tree

Add a device tree for the Microsemi Luton PCB091 evaluation board.

It is based on the work of Lars Povlsen <lars.povlsen@microchip.com>.
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/boot/dts/mscc/Makefile

 # SPDX-License-Identifier: GPL-2.0-only
-dtb-$(CONFIG_SOC_VCOREIII)	+= ocelot_pcb123.dtb ocelot_pcb120.dtb
+dtb-$(CONFIG_SOC_VCOREIII)	+= \
+	luton_pcb091.dtb \
+	ocelot_pcb120.dtb \
+	ocelot_pcb123.dtb
 
 obj-$(CONFIG_BUILTIN_DTB)	+= $(addsuffix .o, $(dtb-y))

arch/mips/boot/dts/mscc/luton_pcb091.dts

+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2020 Microsemi Corporation
+ */
+
+/dts-v1/;
+
+#include "luton.dtsi"
+
+/ {
+	model = "Luton10 PCB091 Reference Board";
+	compatible = "mscc,luton-pcb091", "mscc,luton";
+
+	aliases {
+		serial0 = &uart0;
+	};
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+};
+
+&uart0 {
+	status = "okay";
+};
+
+&i2c0 {
+	status = "okay";
+	i2c-sda-hold-time-ns = <300>;
+};