fdt: Sync up with libfdt

This brings in changes up to commit f9e91a48 in the libfdt repo.
Mostly this is whitespace/minor changes. But there are a few new
features:

- fdt_size_cells() and fdt_address_cells()
- fdt_resize()

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/libfdt/libfdt_internal.h

@@ -12,9 +12,9 @@
 
 #define FDT_CHECK_HEADER(fdt) \
 	{ \
-		int err; \
-		if ((err = fdt_check_header(fdt)) != 0) \
-			return err; \
+		int __err; \
+		if ((__err = fdt_check_header(fdt)) != 0) \
+			return __err; \
 	}
 
 int _fdt_check_node_offset(const void *fdt, int offset);