libfdt: migrate fdt_ro.c to a wrapper of scripts/dtc/libfdt/fdt_ro.c

There is no essential difference between scripts/dtc/libfdt/fdt_ro.c
and lib/libfdt/fdt_ro.c

Migrate to a simple wrapper like the other files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/tools/libfdt/fdt_ro.c b/tools/libfdt/fdt_ro.c
new file mode 100644
index 0000000..8a9735a
--- /dev/null
+++ b/tools/libfdt/fdt_ro.c
@@ -0,0 +1,2 @@
+#include "fdt_host.h"
+#include "../scripts/dtc/libfdt/fdt_ro.c"