perf stat report: Process event update events

Adding processing of event update events, so perf stat report can store
additional info for events - unit,scale,name.

Committer note:

Before:

  # perf stat record -e power/energy-cores/ -a
  ^C
  Performance counter stats for 'system wide':

             77.41 Joules power/energy-cores/

       1.597176695 seconds time elapsed

  # perf stat report

  Performance counter stats for '/home/acme/bin/perf stat record -e power/energy-cores/ -a':

   332,488,114,176      power/energy-cores/

       1.597176695 seconds time elapsed

  #

After, using the same perf.data file generated in the "Before" case
above:

  # perf stat report

  Performance counter stats for '/home/acme/bin/perf stat record -e power/energy-cores/ -a':

             77.41 Joules power/energy-cores/

       1.597176695 seconds time elapsed

  #

Reported-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.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/1446734469-11352-17-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-stat.c

@@ -1736,6 +1736,7 @@ static const char * const report_usage[] = {
 static struct perf_stat perf_stat = {
 	.tool = {
 		.attr		= perf_event__process_attr,
+		.event_update	= perf_event__process_event_update,
 		.thread_map	= process_thread_map_event,
 		.cpu_map	= process_cpu_map_event,
 		.stat_config	= process_stat_config_event,