[media] v4l2-core: remove the old .ioctl BKL replacement

To keep V4L2 drivers that did not yet convert to unlocked_ioctl happy,
the v4l2 core had a .ioctl file operation that took a V4L2 lock.

The last drivers are now converted to unlocked_ioctl, so all this
old code can now be removed.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

include/media/v4l2-device.h

@@ -58,8 +58,6 @@ struct v4l2_device {
 	struct v4l2_ctrl_handler *ctrl_handler;
 	/* Device's priority state */
 	struct v4l2_prio_state prio;
-	/* BKL replacement mutex. Temporary solution only. */
-	struct mutex ioctl_lock;
 	/* Keep track of the references to this struct. */
 	struct kref ref;
 	/* Release function that is called when the ref count goes to 0. */