libfdt: Added missing functions to shared library

Some API function symbols were set as 'local' causing linking errors,
now they are set as global (external).

Signed-off-by: Anders Hedlund <anders.hedlund@windriver.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>

libfdt/version.lds

@@ -48,6 +48,12 @@ LIBFDT_1.2 {
 		fdt_strerror;
 		fdt_offset_ptr;
 		fdt_next_tag;
+		fdt_appendprop;
+		fdt_create_empty_tree;
+		fdt_first_property_offset;
+		fdt_get_property_by_offset;
+		fdt_getprop_by_offset;
+		fdt_next_property_offset;
 
 	local:
 		*;