V4L/DVB (9086): gspca: Use a kref to avoid potentialy blocking forever in disconnect.

Signed-off-by: Frank Zago <frank@zago.net>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/gspca/gspca.h b/drivers/media/video/gspca/gspca.h
index b0bdae1..192dffd 100644
--- a/drivers/media/video/gspca/gspca.h
+++ b/drivers/media/video/gspca/gspca.h
@@ -121,6 +121,7 @@
 	struct video_device vdev;	/* !! must be the first item */
 	struct file_operations fops;
 	struct usb_device *dev;
+	struct kref kref;
 	struct file *capt_file;		/* file doing video capture */
 
 	struct cam cam;				/* device information */