V4L/DVB (8883): w9968cf: Fix order of usb_alloc_urb validation

Fixed order of usb_alloc_urb pointer validation.

Cc: Luca Risolia <luca.risolia@studio.unibo.it>
Signed-off-by: Douglas Schilling Landgraf <dougsland@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/w9968cf.c

@@ -911,14 +911,14 @@ static int w9968cf_start_transfer(struct w9968cf_device* cam)
 
 	for (i = 0; i < W9968CF_URBS; i++) {
 		urb = usb_alloc_urb(W9968CF_ISO_PACKETS, GFP_KERNEL);
-		cam->urb[i] = urb;
 		if (!urb) {
 			for (j = 0; j < i; j++)
 				usb_free_urb(cam->urb[j]);
 			DBG(1, "Couldn't allocate the URB structures")
 			return -ENOMEM;
 		}
 
+		cam->urb[i] = urb;
 		urb->dev = udev;
 		urb->context = (void*)cam;
 		urb->pipe = usb_rcvisocpipe(udev, 1);