usb-serial: handle NULL termios methods as "no hardware changing support"

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 4b1bd7d..426afaa 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -429,6 +429,8 @@
 	/* pass on to the driver specific version of this function if it is available */
 	if (port->serial->type->set_termios)
 		port->serial->type->set_termios(port, old);
+	else
+		tty_termios_copy_hw(tty->termios, old);
 }
 
 static void serial_break (struct tty_struct *tty, int break_state)