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/tty/serial/max3100.c b/drivers/tty/serial/max3100.c
index 7ce3197..e238e80 100644
--- a/drivers/tty/serial/max3100.c
+++ b/drivers/tty/serial/max3100.c
@@ -530,7 +530,7 @@
 			MAX3100_STATUS_OE;
 
 	/* we are sending char from a workqueue so enable */
-	s->port.state->port.tty->low_latency = 1;
+	s->port.state->port.low_latency = 1;
 
 	if (s->poll_time > 0)
 		del_timer_sync(&s->timer);