perf top: Check per-event overwrite term

perf top: Check per-event overwrite term

Per-event overwrite term is not forbidden in 'perf top', which can bring
problems. Because 'perf top' only support non-overwrite mode now.

Add new rules and check regarding to overwrite term for 'perf top'.
- All events either have same per-event term or don't have per-event
  mode setting. Otherwise, it will error out.
- Per-event overwrite term should be consistent as opts->overwrite.
  If not, updating the opts->overwrite according to per-event term.

Make it possible to support either non-overwrite or overwrite mode.
The overwrite mode is forbidden now, which will be removed when the
overwrite mode is supported later.

Signed-off-by: Kan Liang <kan.liang@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1516310792-208685-12-git-send-email-kan.liang@intel.com
[ Renamed perf_top_overwrite_check to perf_top__overwrite_check, to follow existing convention ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>