perf tools: Add event_update user level event

It'll serve as a base event for additional event attributes details,
that are not part of the attr event.

At the moment this event is just a dummy one without any specific
functionality. The type value will distinguish the update event details.
It'll come in the following patches.

The idea for this event is to be extensible for any update that the
event might need in the future.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1445784728-21732-21-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/tool.h b/tools/perf/util/tool.h
index d04d9e5..55de4cf 100644
--- a/tools/perf/util/tool.h
+++ b/tools/perf/util/tool.h
@@ -50,6 +50,7 @@
 			throttle,
 			unthrottle;
 	event_attr_op	attr;
+	event_attr_op	event_update;
 	event_op2	tracing_data;
 	event_oe	finished_round;
 	event_op2	build_id,