perf probe: Split add_perf_probe_events()

The add_perf_probe_events() does 3 things:

 1. convert all perf events to trace events
 2. add all trace events to kernel
 3. cleanup all trace events

But sometimes we need to do something with the trace events.  So split
the funtion into three, so that it can access intermediate trace events
via struct __event_package if needed.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1441368963-11565-1-git-send-email-namhyung@kernel.org


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