batman-adv: update copyright years

update copyright years in order to include 2012
Signed-off-by: NAntonio Quartulli <ordex@autistici.org>

net/batman-adv/bridge_loop_avoidance.c

 /*
- * Copyright (C) 2011 B.A.T.M.A.N. contributors:
+ * Copyright (C) 2011-2012 B.A.T.M.A.N. contributors:
  *
  * Simon Wunderlich
  *

net/batman-adv/bridge_loop_avoidance.h

 /*
- * Copyright (C) 2011 B.A.T.M.A.N. contributors:
+ * Copyright (C) 2011-2012 B.A.T.M.A.N. contributors:
  *
  * Simon Wunderlich
  *