Move the following functions:

  evsel__enable()
  evsel__disable()
  evsel__apply_filter()

to libperf with the following names:

  perf_evsel__enable()
  perf_evsel__disable()
  perf_evsel__apply_filter()

Export only perf_evsel__enable()/disable(), keeping the
perf_evsel__apply_filter() one private for the moment.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-66-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>