perf session: Warn when AUX data has been lost

By default 'perf record' will postprocess the perf.data file to
determine build-ids.  When that happens, the number of lost perf events
is displayed.

Make that also happen for AUX events.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-7-git-send-email-adrian.hunter@intel.com


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