Kernel/TTY: Remove redundant SpinLock from VirtualConsole

VirtualConsole::m_lock was only used in a single place: on_tty_write()
That function is already protected by a global lock, so this second
lock served no purpose whatsoever.

Kernel/TTY/VirtualConsole.cpp

@@ -260,7 +260,6 @@ void VirtualConsole::on_key_pressed(KeyEvent event)
 KResultOr<size_t> VirtualConsole::on_tty_write(const UserOrKernelBuffer& data, size_t size)
 {
     ScopedSpinLock global_lock(ConsoleManagement::the().tty_write_lock());
-    ScopedSpinLock lock(m_lock);
     auto result = data.read_buffered<512>(size, [&](u8 const* buffer, size_t buffer_bytes) {
         for (size_t i = 0; i < buffer_bytes; ++i)
             m_console_impl.on_input(buffer[i]);

Kernel/TTY/VirtualConsole.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -118,7 +118,6 @@ private:
     bool m_graphical { false };
 
     String m_tty_name;
-    RecursiveSpinLock m_lock;
 
 private:
     void initialize();