Fix race conditions that cause broken timer interrupts. Change-Id: I78e13a18d394b1566977e894a1def16a66c9ca5f Reviewed-on: https://review.haiku-os.org/c/haiku/+/5883 Reviewed-by: X512 <danger_mail@list.ru> Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com> Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>