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.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>