posix-timers: Remove pointless irqsafe from hash_lock

All usage of hash_lock is in thread context. No point in using
spin_lock_irqsave()/irqrestore() for a single usage site.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230425183313.249063953@linutronix.de

kernel/time/posix-timers.c

@@ -471,10 +471,9 @@ static void k_itimer_rcu_free(struct rcu_head *head)
 static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
 {
 	if (it_id_set) {
-		unsigned long flags;
-		spin_lock_irqsave(&hash_lock, flags);
+		spin_lock(&hash_lock, flags);
 		hlist_del_rcu(&tmr->t_hash);
-		spin_unlock_irqrestore(&hash_lock, flags);
+		spin_unlock(&hash_lock, flags);
 	}
 	put_pid(tmr->it_pid);
 	sigqueue_free(tmr->sigq);