perf probe: Fix memory leaks in add_perf_probe_events

Fix several memory leaks of pkgs and tevs in add_perf_probe_events().

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org
LKML-Reference: <4C577ADC.1000309@hitachi.com>

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>