libfdt: Downgrade to version 1.4.6-9

Version 1.4.7 introduces a big performance hit to functions that access
the FDT. Downgrade the library to version 1.4.6-9, before the changes
that introduce the problem. Version 1.4.6 isn't used because one of the
libfdt files (fdt_overlay.c) is missing the license header. This
problem is also fixed in 1.4.6-9.

This version corresponds to commit <aadd0b65c987> checks: centralize
printing of property names in failure messages.

Fixes ARM-software/tf-issues#643

Change-Id: I73c05f2b1f994bcdcc4366131ce0647553cdcfb8
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/lib/libfdt/fdt_overlay.c b/lib/libfdt/fdt_overlay.c
index 5fdab6c..bf75388 100644
--- a/lib/libfdt/fdt_overlay.c
+++ b/lib/libfdt/fdt_overlay.c
@@ -697,7 +697,7 @@
 	int len = 0, namelen;
 	const char *name;
 
-	FDT_RO_PROBE(fdt);
+	FDT_CHECK_HEADER(fdt);
 
 	for (;;) {
 		name = fdt_get_name(fdt, nodeoffset, &namelen);
@@ -866,8 +866,8 @@
 	uint32_t delta = fdt_get_max_phandle(fdt);
 	int ret;
 
-	FDT_RO_PROBE(fdt);
-	FDT_RO_PROBE(fdto);
+	FDT_CHECK_HEADER(fdt);
+	FDT_CHECK_HEADER(fdto);
 
 	ret = overlay_adjust_local_phandles(fdto, delta);
 	if (ret)