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/FileSystem/SysFS/Registry.h

@@ -32,7 +32,7 @@ public:
 
 private:
     NonnullRefPtr<SysFSRootDirectory> m_root_directory;
-    Spinlock m_root_directory_lock;
+    Spinlock m_root_directory_lock { LockRank::None };
 };
 
 }