perf evsel: Ditch evsel->handler.data field

Not needed since this cset:

  fcf65bf149af: perf evsel: Cache associated event_format

So lets trim this struct a bit.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-j8setslokt0goiwxq9dogzqm@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 0ce4694..f36d24a 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1650,9 +1650,9 @@
 			continue;
 
 		err = -EEXIST;
-		if (evsel->handler.func != NULL)
+		if (evsel->handler != NULL)
 			goto out;
-		evsel->handler.func = assocs[i].handler;
+		evsel->handler = assocs[i].handler;
 	}
 
 	err = 0;