perf evlist: Simplify set_maps() logic

Don't need to check for NULL when "putting" evlist->maps and
evlist->threads because the "put" functions already do that.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Link: http://lkml.kernel.org/r/1441699142-18905-3-git-send-email-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evlist.c

@@ -1156,14 +1156,10 @@ int perf_evlist__set_maps(struct perf_evlist *evlist,
 			  struct cpu_map *cpus,
 			  struct thread_map *threads)
 {
-	if (evlist->cpus)
 	cpu_map__put(evlist->cpus);
-
 	evlist->cpus = cpus;
 
-	if (evlist->threads)
 	thread_map__put(evlist->threads);
-
 	evlist->threads = threads;
 
 	return perf_evlist__propagate_maps(evlist, false);