V4L/DVB (13479): cxusb: fix compile warning

Fix this trivial compile warning:

v4l/cxusb.c:1195: warning: unused variable 'n'
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/dvb-usb/cxusb.c

@@ -1189,7 +1189,6 @@ static struct atbm8830_config mygica_d689_atbm8830_cfg = {
 static int cxusb_mygica_d689_frontend_attach(struct dvb_usb_adapter *adap)
 {
 	struct dvb_usb_device *d = adap->dev;
-	int n;
 
 	/* Select required USB configuration */
 	if (usb_set_interface(d->udev, 0, 0) < 0)