batman-adv: Update copyright years

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
diff --git a/net/batman-adv/ring_buffer.c b/net/batman-adv/ring_buffer.c
index f1ccfa7..fd63951 100644
--- a/net/batman-adv/ring_buffer.c
+++ b/net/batman-adv/ring_buffer.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2007-2011 B.A.T.M.A.N. contributors:
+ * Copyright (C) 2007-2012 B.A.T.M.A.N. contributors:
  *
  * Marek Lindner
  *