selinux: update my email address

Update my email address since epoch.ncsc.mil no longer exists.
MAINTAINERS and CREDITS are already correct.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 52f3c55..f14ae9c 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -1,7 +1,7 @@
 /*
  * Implementation of the kernel access vector cache (AVC).
  *
- * Authors:  Stephen Smalley, <sds@epoch.ncsc.mil>
+ * Authors:  Stephen Smalley, <sds@tycho.nsa.gov>
  *	     James Morris <jmorris@redhat.com>
  *
  * Update:   KaiGai, Kohei <kaigai@ak.jp.nec.com>