libfdt: migrate include/libfdt_env.h to a wrapper

libfdt_env.h is supposed to provide system-dependent defines.

scripts/dtc/libfdt/libfdt_env.h from upstream DTC is suitable
for user-space, so we should use this for USE_HOSTCC case.

For compiling U-Boot, we need to override such system-dependent
defines, so use <linux/libfdt_env.h> imported from Linux.

<libfdt.h> selects a proper one.  Maybe, we should split header
inclusion completely, but I do not want too many patches at one.

I can rip off the include/libfdt_env.h from HOST_EXTRACFLAGS.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/libfdt_env.h b/include/libfdt_env.h
index ea26979..d7e9d32 100644
--- a/include/libfdt_env.h
+++ b/include/libfdt_env.h
@@ -1,24 +1,5 @@
-/*
- * libfdt - Flat Device Tree manipulation (build/run environment adaptation)
- * Copyright (C) 2007 Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
- * Original version written by David Gibson, IBM Corporation.
- *
- * SPDX-License-Identifier:	LGPL-2.1+
- */
-
-#ifndef _LIBFDT_ENV_H
-#define _LIBFDT_ENV_H
-
-#include "compiler.h"
-#include "linux/types.h"
-
-typedef __be16 fdt16_t;
-typedef __be32 fdt32_t;
-typedef __be64 fdt64_t;
-
-#define fdt32_to_cpu(x)		be32_to_cpu(x)
-#define cpu_to_fdt32(x)		cpu_to_be32(x)
-#define fdt64_to_cpu(x)		be64_to_cpu(x)
-#define cpu_to_fdt64(x)		cpu_to_be64(x)
-
-#endif /* _LIBFDT_ENV_H */
+#ifdef USE_HOSTCC
+#include "../scripts/dtc/libfdt/libfdt_env.h"
+#else
+#include <linux/libfdt_env.h>
+#endif
diff --git a/tools/Makefile b/tools/Makefile
index f8731e7..d3387fa 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -242,7 +242,7 @@
 # Define __KERNEL_STRICT_NAMES to prevent typedef overlaps
 # Define _GNU_SOURCE to obtain the getline prototype from stdio.h
 #
-HOST_EXTRACFLAGS += -include $(srctree)/include/libfdt_env.h \
+HOST_EXTRACFLAGS += -include $(srctree)/include/compiler.h \
 		$(patsubst -I%,-idirafter%, $(filter -I%, $(UBOOTINCLUDE))) \
 		-I$(srctree)/lib/libfdt \
 		-I$(srctree)/tools \