tty: Mark tty_del_file and __tty_hangup static

Nothing outside of drivers/tty/tty_io.c references these functions, so
mark them static.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_io.c

@@ -236,7 +236,7 @@ void tty_free_file(struct file *file)
 }
 
 /* Delete file from its tty */
-void tty_del_file(struct file *file)
+static void tty_del_file(struct file *file)
 {
 	struct tty_file_private *priv = file->private_data;
 
@@ -554,7 +554,7 @@ EXPORT_SYMBOL_GPL(tty_wakeup);
  *		  tasklist_lock to walk task list for hangup event
  *		    ->siglock to protect ->signal/->sighand
  */
-void __tty_hangup(struct tty_struct *tty)
+static void __tty_hangup(struct tty_struct *tty)
 {
 	struct file *cons_filp = NULL;
 	struct file *filp, *f = NULL;