perf tools, tools lib traceevent: Rename "pevent" member of struct tep_event to "tep"

The member "pevent" of the struct tep_event is renamed to "tep". This
makes the struct consistent with the chosen naming convention:

  tep (trace event parser), instead of the old pevent.

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/linux-trace-devel/20190401132111.13727-3-tstoyanov@vmware.com
Link: http://lkml.kernel.org/r/20190401164344.627724996@goodmis.org


Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>