perf evsel: Add functions to close evsel on a CPU

Refactor the existing all CPU function to use the per CPU close
internally.

Export APIs to close per CPU.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20191121001522.180827-7-andi@firstfloor.org


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