Enable histograms for events/ftrace/timerlat and osnoise

[Daniel Bristot de Oliveira]

Hi Steven

I would like to collect histograms from timerlat and osnoise tracers event,
but I cannot collect them because they are not tracepoints but... tracer
events. So...

  # ls /sys/kernel/tracing/events/ftrace/timerlat/
  format	hist

no hist, filter, trigger files...

How hard would it be to enable histograms to the ftrace/osnoise and
ftrace/timerlat events?

This will allow me to reduce the overhead of rtla timerlat and rtla osnoise
tools...

Thanks in advance, Stephen!
-- Denny