USB: keyspan: fix bogus array index

The outcont_endpoints array was indexed using the port minor number
(which can be greater than the array size) rather than the device port
number.

Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/keyspan.c

@@ -1559,7 +1559,7 @@ static int keyspan_usa26_send_setup(struct usb_serial *serial,
 	d_details = s_priv->device_details;
 	device_port = port->number - port->serial->minor;
 
-	outcont_urb = d_details->outcont_endpoints[port->number];
+	outcont_urb = d_details->outcont_endpoints[device_port];
 	this_urb = p_priv->outcont_urb;
 
 	dev_dbg(&port->dev, "%s - endpoint %d\n", __func__, usb_pipeendpoint(this_urb->pipe));