perf intel-pt: Prepare to synthesize PEBS samples

Add infrastructure to prepare for synthesizing PEBS samples but leave
the actual synthesis to later patches.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190610072803.10456-5-adrian.hunter@intel.com


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