Fix missing license header.

libsel4vspace/src/vspace.c

diff --git a/libsel4vspace/src/vspace.c b/libsel4vspace/src/vspace.c
index ee15e5a..fd5ae50 100644
--- a/libsel4vspace/src/vspace.c
+++ b/libsel4vspace/src/vspace.c
@@ -1,3 +1,12 @@
+/*
+ * Copyright 2016, NICTA
+ *
+ * This software may be distributed and modified according to the terms of
+ * the BSD 2-Clause license. Note that NO WARRANTY is provided.
+ * See "LICENSE_BSD2.txt" for details.
+ *
+ * @TAG(NICTA_BSD)
+ */
 
 #include <autoconf.h>
 #include <vspace/vspace.h>