lockdep: Use str_plural() to fix Coccinelle warning

Fixes the following Coccinelle/coccicheck warning reported by
string_choices.cocci:

	opportunity for str_plural(depth)
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240528120008.403511-2-thorsten.blum@toblux.com

kernel/locking/lockdep.c

@@ -785,7 +785,7 @@ static void lockdep_print_held_locks(struct task_struct *p)
 		printk("no locks held by %s/%d.\n", p->comm, task_pid_nr(p));
 	else
 		printk("%d lock%s held by %s/%d:\n", depth,
-		       depth > 1 ? "s" : "", p->comm, task_pid_nr(p));
+		       str_plural(depth), p->comm, task_pid_nr(p));
 	/*
 	 * It's not reliable to print a task's held locks if it's not sleeping
 	 * and it's not the current task.