perf intel-pt: Fix missing stack clear

perf intel-pt: Fix missing stack clear

commit 12b7080609097753fd8198cc1daf589be3ec1cca upstream.

The return compression stack must be cleared whenever there is a PSB. Fix
one case where that was not happening.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>