rtla: Add function to report missed events

rtla: Add function to report missed events

Add osnoise_report_missed_events to be used to report the number
of missed events either during or after an osnoise or timerlat run.
Also, display the percentage of missed events compared to the total
number of received events.

If an unknown number of missed events was reported during the run, the
entire number of missed events is reported as unknown.

Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250123142339.990300-4-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>