boards: amlogic: Add FriendlyElec NanoPi K2 board support

This adds platform code for the FriendlyElec NanoPi K2 board based on a
Meson GXBB (S905) SoC with the Meson GXBB configuration.

This initial submission only supports:
- UART
- MMC/SDCard
- Ethernet
- Reset Controller
- Clock controller

Cc: Yuefei Tan <yftan@friendlyarm.com>
Signed-off-by: Thomas McKahan <tonymckahan@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

include/configs/nanopi-k2.h

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Configuration for NANOPI-K2
+ * (C) Copyright 2018 Thomas McKahan
+ */
+
+#ifndef __CONFIG_H
+#define __CONFIG_H
+
+#define CONFIG_MISC_INIT_R
+
+/* Serial setup */
+
+#define MESON_FDTFILE_SETTING "fdtfile=amlogic/meson-gxbb-nanopi-k2.dtb\0"
+
+#include <configs/meson-gx-common.h>
+
+#endif /* __CONFIG_H */