TTY: move low_latency to tty_port

One point is to have less places where we actually need tty pointer.
The other is that low_latency is bound to buffer processing and
buffers are now in tty_port. So it makes sense to move low_latency to
tty_port too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index 43ea059..3860e79 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -860,7 +860,7 @@
 		tty->driver_data = tp;
 		tty->winsize.ws_row = tp->view.rows - 2;
 		tty->winsize.ws_col = tp->view.cols;
-		tty->low_latency = 0;
+		tp->port.low_latency = 0;
 		/* why to reassign? */
 		tty_port_tty_set(&tp->port, tty);
 		tp->inattr = TF_INPUT;
@@ -893,7 +893,7 @@
 	}
 
 	tty_port_tty_set(&tp->port, tty);
-	tty->low_latency = 0;
+	tp->port.low_latency = 0;
 	tty->winsize.ws_row = tp->view.rows - 2;
 	tty->winsize.ws_col = tp->view.cols;