USB: keyspan: fix bogus array index

commit a07088098a650267b2eda689538133a324b9523f upstream.

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.

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

diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
index a39ddd1..253bff6 100644
--- a/drivers/usb/serial/keyspan.c
+++ b/drivers/usb/serial/keyspan.c
@@ -1705,7 +1705,7 @@
 	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;
 
 	dbg("%s - endpoint %d", __func__, usb_pipeendpoint(this_urb->pipe));