iwlegacy: remove unused IL_AC_UNSET define

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>

drivers/net/wireless/iwlegacy/4965.c

@@ -40,8 +40,6 @@
 #include "common.h"
 #include "4965.h"
 
-#define IL_AC_UNSET -1
-
 /**
  * il_verify_inst_sparse - verify runtime uCode image in card vs. host,
  *   using sample data 100 bytes apart.  If these sample points are good,