perf intel-pt: Move code in intel_pt_synth_events() to simplify attr setting

intel_pt_synth_events() uses the same attr structure to create each event.
Move the code around a bit to simplify that.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-33-git-send-email-adrian.hunter@intel.com


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