TTY: wake up processes last at hangup

Move wake up of processes on blocked-open and modem-status wait queues
to after port shutdown at hangup.

This way the woken up processes can use the ASYNC_INITIALIZED flag to
detect port shutdown.

Note that this is the order currently used by serial-core.

Signed-off-by: Johan Hovold <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/tty_port.c

···
 	}
 	port->tty = NULL;
 	spin_unlock_irqrestore(&port->lock, flags);
+	tty_port_shutdown(port);
 	wake_up_interruptible(&port->open_wait);
 	wake_up_interruptible(&port->delta_msr_wait);
-	tty_port_shutdown(port);
 }
 EXPORT_SYMBOL(tty_port_hangup);