tty: Unexport system-wide tty_mutex

tty_mutex is a core, system-wide lock; there is no reason for any
code outside the tty core to have direct access.

Signed-off-by: Peter Hurley <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/tty_io.c

···
 
 LIST_HEAD(tty_drivers);			/* linked list of tty drivers */
 
-/* Mutex to protect creating and releasing a tty. This is shared with
-   vt.c for deeply disgusting hack reasons */
+/* Mutex to protect creating and releasing a tty */
 DEFINE_MUTEX(tty_mutex);
-EXPORT_SYMBOL(tty_mutex);
 
 /* Spinlock to protect the tty->tty_files list */
 DEFINE_SPINLOCK(tty_files_lock);