perf intel-pt: Ensure IP is zero when state is INTEL_PT_STATE_NO_IP

A value of zero is used to indicate that there is no IP. Ensure the
value is zero when the state is INTEL_PT_STATE_NO_IP.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-5-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>