TTY: switch tty_insert_flip_string

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

tty_insert_flip_string this time.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 66d9e08..3ddd7a1 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -773,9 +773,10 @@
 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
 
 	if (urb->actual_length) {
-		tty = tty_port_tty_get(&mos7840_port->port->port);
+		struct tty_port *tport = &mos7840_port->port->port;
+		tty = tty_port_tty_get(tport);
 		if (tty) {
-			tty_insert_flip_string(tty, data, urb->actual_length);
+			tty_insert_flip_string(tport, data, urb->actual_length);
 			tty_flip_buffer_push(tty);
 			tty_kref_put(tty);
 		}