Kernel: Make TTY write lock a mutex instead of a spinlock

The mutex could not be locked while processing ANSI DGR in VTTY

kernel/include/kernel/Terminal/TTY.h

@@ -105,7 +105,7 @@ namespace Kernel
 	protected:
 		Mutex m_mutex;
 
-		RecursiveSpinLock m_write_lock;
+		Mutex m_write_lock;
 		ThreadBlocker m_write_blocker;
 	};