rv: Add automatic cleanup handlers for per-task HA monitors

rv: Add automatic cleanup handlers for per-task HA monitors

Hybrid automata monitors may start timers, depending on the model, these
may remain active on an exiting task and cause false positives or even
access freed memory.

Add an enable/disable hook in the HA code, currently only populated by
the per-task handler for registration and deregistration.
This hooks to the sched_process_exit event and ensures the timer is
stopped for every exiting task. The handler is enabled automatically but
may be disabled, for instance if the monitor uses the event for another
purpose (but should still manually ensure timers are stopped).

Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type")
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260601153840.124372-8-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>