perf top: Move toggling event logic into hists browser

Current 'f' key action to enable/disable events won't work if there're
more than one event since perf_evsel_menu__run() doesn't return the key.
So move it to the hists browser loop so that it can be processed as like
other key action, and it's more natural to handle it there IMHO.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1434858076-6533-1-git-send-email-namhyung@kernel.org


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