locking/lock_events: Add locking events for rtmutex slow paths

Add locking events for rtlock_slowlock() and rt_mutex_slowlock() for
profiling the slow path behavior of rt_spin_lock() and rt_mutex_lock().

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250307232717.1759087-4-boqun.feng@gmail.com