tty: Relocate tty_ldisc_halt() to avoid forward declaration

tty_ldisc_halt() will use the file-scoped function, tty_ldisc_wait_idle(),
in the following patch.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_ldisc.c

@@ -498,29 +498,6 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
 	}
 }
 
-/**
- *	tty_ldisc_halt		-	shut down the line discipline
- *	@tty: tty device
- *
- *	Shut down the line discipline and work queue for this tty device.
- *	The TTY_LDISC flag being cleared ensures no further references can
- *	be obtained while the delayed work queue halt ensures that no more
- *	data is fed to the ldisc.
- *
- *	You need to do a 'flush_scheduled_work()' (outside the ldisc_mutex)
- *	in order to make sure any currently executing ldisc work is also
- *	flushed.
- */
-
-static int tty_ldisc_halt(struct tty_struct *tty)
-{
-	int scheduled;
-	clear_bit(TTY_LDISC, &tty->flags);
-	scheduled = cancel_work_sync(&tty->port->buf.work);
-	set_bit(TTY_LDISC_HALTED, &tty->flags);
-	return scheduled;
-}
-
 /**
  *	tty_ldisc_flush_works	-	flush all works of a tty
  *	@tty: tty device to flush works for
@@ -550,6 +527,29 @@ static int tty_ldisc_wait_idle(struct tty_struct *tty, long timeout)
 	return ret > 0 ? 0 : -EBUSY;
 }
 
+/**
+ *	tty_ldisc_halt		-	shut down the line discipline
+ *	@tty: tty device
+ *
+ *	Shut down the line discipline and work queue for this tty device.
+ *	The TTY_LDISC flag being cleared ensures no further references can
+ *	be obtained while the delayed work queue halt ensures that no more
+ *	data is fed to the ldisc.
+ *
+ *	You need to do a 'flush_scheduled_work()' (outside the ldisc_mutex)
+ *	in order to make sure any currently executing ldisc work is also
+ *	flushed.
+ */
+
+static int tty_ldisc_halt(struct tty_struct *tty)
+{
+	int scheduled;
+	clear_bit(TTY_LDISC, &tty->flags);
+	scheduled = cancel_work_sync(&tty->port->buf.work);
+	set_bit(TTY_LDISC_HALTED, &tty->flags);
+	return scheduled;
+}
+
 /**
  *	tty_ldisc_hangup_halt - halt the line discipline for hangup
  *	@tty: tty being hung up