perf evswitch: Move switch logic to use in other tools

Now other tools that want switching can use an evswitch for that, just
set it up and add it to the PERF_RECORD_SAMPLE processing function.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: William Cohen <wcohen@redhat.com>
Link: https://lkml.kernel.org/n/tip-b1trj1q97qwfv251l66q3noj@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evswitch.h

@@ -13,4 +13,6 @@ struct evswitch {
 	bool	     show_on_off_events;
 };
 
+bool evswitch__discard(struct evswitch *evswitch, struct evsel *evsel);
+
 #endif /* __PERF_EVSWITCH_H */