mips: luton: DT: Add pcb090

This prepares individual device trees for MSCC luton-based reference
boards - pcb090 and pcb091.

Note: Even though the devices trees are quite common, they will differ
significantly in coming patches.

Signed-off-by: Lars Povlsen <lars.povlsen@microchip.com>

arch/mips/dts/luton_pcb090.dts

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2018 Microsemi Corporation
+ */
+
+/dts-v1/;
+#include "mscc,luton.dtsi"
+
+/ {
+	model = "Luton26 PCB090 Reference Board";
+	compatible = "mscc,luton-pcb090", "mscc,luton";
+
+	aliases {
+		serial0 = &uart0;
+		spi0 = &spi0;
+	};
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+	};
+};
+
+&uart0 {
+	status = "okay";
+};
+
+&spi0 {
+	status = "okay";
+	spi-flash@0 {
+		compatible = "spi-flash";
+		spi-max-frequency = <18000000>; /* input clock */
+		reg = <0>; /* CS0 */
+		spi-cs-high;
+	};
+};
+