Unconditionaly initialize any spin lock passed to pthread_spin_init(). While

makeing sure the spinlock isn't already in use might be a nice feature to
have in theory, it's hard to implement in practice since the passed in
pointer may not be NULL, but still be an invalid value (i.e. 1..2..3.. etc).

lib/libthr/thread/thr_spinlock.c

@@ -80,10 +80,6 @@ _pthread_spin_init(pthread_spinlock_t *lock, int pshared)
 {
 	struct pthread_spinlock *s;
 
-	if (*lock != NULL) {
-		if ((*lock)->s_magic == THR_SPIN_MAGIC)
-			return (EBUSY);
-	}
 	s = (struct pthread_spinlock *)malloc(sizeof(struct pthread_spinlock));
 	if (s == NULL)
 		return (ENOMEM);