perf sched map: Display only given cpus

perf sched map: Display only given cpus

Introducing --cpus option that will display only given cpus. Could be
used together with color-cpus option.

  $ perf sched map  --cpus 0,1
        *A0   309999.786924 secs A0 => rcu_sched:7
        *.    309999.786930 secs
    *B0  .    309999.786931 secs B0 => rcuos/2:25
     B0 *A0   309999.786947 secs

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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/1460467771-26532-9-git-send-email-jolsa@kernel.org
[ Added entry to man page ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>