sched/psi: Delete the 'update_total' function parameter from update_triggers()

The 'update_total' parameter of update_triggers() is always true after the
previous commit:

  80cc1d1d ("sched/psi: Avoid updating PSI triggers and ->rtpoll_total when there are no state changes")

If the 'changed_states & group->rtpoll_states' condition is true,
'new_stall' in update_triggers() will be true, and then 'update_total'
should also be true.

So update_total is redundant - remove it.

[ mingo: Changelog updates ]

Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/202310101645437859599@zte.com.cn