libfdt: Add some missing symbols to version.lds

Several functions in the header file were missing from the version.lds
script, meaning that they couldn't be used from a libfdt shared library.

Reported by Ken Aaker, via github issue tracker.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
diff --git a/libfdt/version.lds b/libfdt/version.lds
index f19f157..1f4e1ea 100644
--- a/libfdt/version.lds
+++ b/libfdt/version.lds
@@ -57,6 +57,10 @@
 		fdt_next_property_offset;
 		fdt_first_subnode;
 		fdt_next_subnode;
+		fdt_address_cells;
+		fdt_size_cells;
+		fdt_stringlist_contains;
+		fdt_resize;
 
 	local:
 		*;