Kernel: Require lock rank for Spinlock construction

All users which relied on the default constructor use a None lock rank
for now. This will make it easier to in the future remove LockRank and
actually annotate the ranks by searching for None.

Kernel/Memory/VMObject.h

@@ -65,7 +65,7 @@ protected:
     IntrusiveListNode<VMObject> m_list_node;
     FixedArray<RefPtr<PhysicalPage>> m_physical_pages;
 
-    mutable RecursiveSpinlock m_lock;
+    mutable RecursiveSpinlock m_lock { LockRank::None };
 
 private:
     VMObject& operator=(VMObject const&) = delete;