perf intel-pt: Fix sync_switch INTEL_PT_SS_NOT_TRACING

perf intel-pt: Fix sync_switch INTEL_PT_SS_NOT_TRACING

BugLink: http://bugs.launchpad.net/bugs/1807469
commit dbcb82b93f3e8322891e47472c89e63058b81e99 upstream.

sync_switch is a facility to synchronize decoding more closely with the
point in the kernel when the context actually switched.

In one case, INTEL_PT_SS_NOT_TRACING state was not correctly
transitioning to INTEL_PT_SS_TRACING state due to a missing case clause.
Add it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1527762225-26024-2-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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>