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/sierra.c b/drivers/usb/serial/sierra.c
index af06f2f..64e53fd 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -583,7 +583,7 @@
 		if (urb->actual_length) {
 			tty = tty_port_tty_get(&port->port);
 			if (tty) {
-				tty_insert_flip_string(tty, data,
+				tty_insert_flip_string(&port->port, data,
 					urb->actual_length);
 				tty_flip_buffer_push(tty);