tools lib traceevent, perf tools: Rename 'enum pevent_flag' to 'enum tep_flag'

In order to make libtraceevent into a proper library, variables, data
structures and functions require a unique prefix to prevent name space
conflicts. That prefix will be "tep_" and not "pevent_". This changes
pevent_get_page_size API and enum pevent_flag to enum tep_flag

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
Cc: linux-trace-devel@vger.kernel.org
Link: http://lkml.kernel.org/r/20180808180701.623942406@goodmis.org


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