ARM: dts: uniphier: add ProXstream2 and PH1-LD6b SoC/board support

Initial version of DTSI for ProXstream2 and PH1-LD6b and DTS for
PH1-LD6b reference board.

Import from Linux with some adjustments:
  - Use SPDX-License-Identifier
  - Add clock-frequency to serial nodes
  - Drop unusable nodes from -ref.dts

While I am here, sort Makefile entries alphabetically.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/dts/uniphier-ph1-ld6b-ref.dts b/arch/arm/dts/uniphier-ph1-ld6b-ref.dts
new file mode 100644
index 0000000..58dc20e
--- /dev/null
+++ b/arch/arm/dts/uniphier-ph1-ld6b-ref.dts
@@ -0,0 +1,59 @@
+/*
+ * Device Tree Source for UniPhier PH1-LD6b Reference Board
+ *
+ * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ */
+
+/dts-v1/;
+/include/ "uniphier-ph1-ld6b.dtsi"
+/include/ "uniphier-ref-daughter.dtsi"
+
+/ {
+	model = "UniPhier PH1-LD6b Reference Board";
+	compatible = "socionext,ph1-ld6b-ref", "socionext,ph1-ld6b";
+
+	memory {
+		device_type = "memory";
+		reg = <0x80000000 0x80000000>;
+	};
+
+	chosen {
+		bootargs = "console=ttyS0,115200";
+		stdout-path = &serial0;
+	};
+
+	aliases {
+		serial0 = &serial0;
+		serial1 = &serial1;
+		serial2 = &serial2;
+		i2c0 = &i2c0;
+		i2c1 = &i2c1;
+		i2c2 = &i2c2;
+		i2c3 = &i2c3;
+		i2c4 = &i2c4;
+		i2c5 = &i2c5;
+		i2c6 = &i2c6;
+	};
+};
+
+&serial0 {
+	status = "okay";
+};
+
+&serial1 {
+	status = "okay";
+};
+
+&serial2 {
+	status = "okay";
+};
+
+&i2c0 {
+	status = "okay";
+};
+
+/* for U-boot only */
+&serial0 {
+       u-boot,dm-pre-reloc;
+};