TTY: add tty_port_tty_wakeup helper

It allows for cleaning up on a considerable amount of places. They did
port_get, wakeup, kref_put. Now the only thing needed is to call
tty_port_tty_wakeup which does exactly that.

One exception is ifx6x60 where tty_wakeup was open-coded. We now call
tty_wakeup properly there.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index e0ebec3..e956eae 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -932,7 +932,6 @@
 static void mos7720_bulk_out_data_callback(struct urb *urb)
 {
 	struct moschip_port *mos7720_port;
-	struct tty_struct *tty;
 	int status = urb->status;
 
 	if (status) {
@@ -946,11 +945,8 @@
 		return ;
 	}
 
-	tty = tty_port_tty_get(&mos7720_port->port->port);
-
-	if (tty && mos7720_port->open)
-		tty_wakeup(tty);
-	tty_kref_put(tty);
+	if (mos7720_port->open)
+		tty_port_tty_wakeup(&mos7720_port->port->port);
 }
 
 /*