tools/memory-model: Fix reference to litmus test in recipes.txt

The name of litmus test doesn't match the one described below.
Fix the name of litmus test.

Acked-by: Andrea Parri <[e-mail]>
Acked-by: Joel Fernandes (Google) <[e-mail]>
Signed-off-by: Akira Yokosawa <[e-mail]>
Signed-off-by: Paul E. McKenney <[e-mail]>

tools/memory-model/Documentation/recipes.txt

···
 locking will be seen as ordered by CPUs not holding that lock.
 Consider this example:
 
-	/* See Z6.0+pooncerelease+poacquirerelease+fencembonceonce.litmus. */
+	/* See Z6.0+pooncelock+pooncelock+pombonce.litmus. */
 	void CPU0(void)
 	{
 		spin_lock(&mylock);