tracing: remove stats from struct tracer

Remove unused field @stats from struct tracer.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AA8579B.4020706@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.h

@@ -382,7 +382,6 @@ struct tracer {
 	struct tracer		*next;
 	int			print_max;
 	struct tracer_flags	*flags;
-	struct tracer_stat	*stats;
 };