removing unnecessary assert

kern/thread/synch.c

@@ -187,8 +187,7 @@ void lock_destroy(struct lock * lock)
 void lock_acquire(struct lock * lock)
 {
   KASSERT(lock);
-  KASSERT(lock_do_i_hold(lock));
-  
+
   spinlock_acquire(&(lock->spin));
   
   while (lock->owner)