perf evlist: Remove cpus and threads arguments from perf_evlist__new()

It's almost always used with NULL for both arguments.  Get rid of the
arguments from the signature and use perf_evlist__set_maps() if needed.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1362987798-24969-1-git-send-email-namhyung@kernel.org
[ committer note: replaced spaces with tabs in some of the affected lines ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>