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/opticon.c b/drivers/usb/serial/opticon.c
index c6bfb83..d3b74e5 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -57,7 +57,7 @@
 	if (!tty)
 		return;
 
-	tty_insert_flip_string(tty, buf, len);
+	tty_insert_flip_string(&port->port, buf, len);
 	tty_flip_buffer_push(tty);
 	tty_kref_put(tty);
 }