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.dtsi b/arch/arm/dts/uniphier-ph1-ld6b.dtsi
new file mode 100644
index 0000000..cf02e62
--- /dev/null
+++ b/arch/arm/dts/uniphier-ph1-ld6b.dtsi
@@ -0,0 +1,31 @@
+/*
+ * Device Tree Source for UniPhier PH1-LD6b SoC
+ *
+ * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+	X11
+ */
+
+/*
+ * PH1-LD6b consists of two silicon dies: D-chip and A-chip.
+ * The D-chip (digital chip) is the same as the ProXstream2 die.
+ * Reuse the ProXstream2 device tree with some properties overridden.
+ */
+/include/ "uniphier-proxstream2.dtsi"
+
+/ {
+	compatible = "socionext,ph1-ld6b";
+};
+
+/* UART3 unavilable: the pads are not wired to the package balls */
+&serial3 {
+	status = "disabled";
+};
+
+/*
+ * PH1-LD6b and ProXstream2 have completely different packages,
+ * which makes the pinctrl driver unshareable.
+ */
+&pinctrl {
+	compatible = "socionext,ph1-ld6b-pinctrl", "syscon";
+};