perf evsel: Ensure reserved member of PERF_SAMPLE_CPU is zero in perf_event__synthesize_sample()

PERF_SAMPLE_CPU contains the cpu number in the first 4 bytes and the
second 4 bytes are reserved. Ensure the reserved bytes are zero in
perf_event__synthesize_sample().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1516108492-21401-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evsel.c

@@ -2533,6 +2533,7 @@ int perf_event__synthesize_sample(union perf_event *event, u64 type,
 
 	if (type & PERF_SAMPLE_CPU) {
 		u.val32[0] = sample->cpu;
+		u.val32[1] = 0;
 		if (swapped) {
 			/*
 			 * Inverse of what is done in perf_evsel__parse_sample