[media] usbvision: convert to unlocked_ioctl

Convert driver to use core-assisted locking.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/usbvision/usbvision.h b/drivers/media/video/usbvision/usbvision.h
index cc4e96c..2271ede 100644
--- a/drivers/media/video/usbvision/usbvision.h
+++ b/drivers/media/video/usbvision/usbvision.h
@@ -391,7 +391,7 @@
 	unsigned char iface;						/* Video interface number */
 	unsigned char ifaceAlt;			/* Alt settings */
 	unsigned char Vin_Reg2_Preset;
-	struct mutex               lock;
+	struct mutex v4l2_lock;
 	struct timer_list powerOffTimer;
 	struct work_struct powerOffWork;
 	int power;							/* is the device powered on? */