rtla/timerlat: Unify params struct

rtla/timerlat: Unify params struct

Instead of having separate structs timerlat_top_params and
timerlat_hist_params, use one struct timerlat_params for both.

This allows code using the structs to be shared between timerlat-top and
timerlat-hist.

Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Link: https://lore.kernel.org/20250218145859.27762-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>