perf header: Delete an unnecessary check before the calling free_event_desc()

The free_event_desc() function tests whether its argument is NULL and
then returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: kernel-janitors@vger.kernel.org
Link: http://lkml.kernel.org/r/558C2ABA.3000603@users.sourceforge.netSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/header.c

@@ -1063,7 +1063,6 @@ read_event_desc(struct perf_header *ph, int fd)
 	free(buf);
 	return events;
 error:
-	if (events)
 	free_event_desc(events);
 	events = NULL;
 	goto out;