Fix forgotten license comments

diff --git a/selinux/chcon.c b/selinux/chcon.c
index 80a030f..55c2522 100644
--- a/selinux/chcon.c
+++ b/selinux/chcon.c
@@ -4,6 +4,8 @@
  * Port to busybox: KaiGai Kohei <kaigai@kaigai.gr.jp>
  *
  * Copyright (C) 2006 - 2007 KaiGai Kohei <kaigai@kaigai.gr.jp>
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
  */
 #include <getopt.h>
 #include <selinux/context.h>