tools lib traceevent: Rename input arguments and local variables of libtraceevent from pevent to tep

"pevent" to "tep" renaming of:
 - all "pevent" input arguments of libtraceevent internal functions.
 - all local "pevent" variables of libtraceevent.

This makes the implementation consistent with the chosen naming
convention, tep (trace event parser), and will avoid any confusion with
the old pevent name

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/20190401132111.13727-5-tstoyanov@vmware.com
Link: http://lkml.kernel.org/r/20190401164344.944953447@goodmis.org


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