usb: gadget: uvc: drop vb2_ops_wait_prepare/finish

Since commit 8878598 ("media: vb2: use lock if wait_prepare/finish
are NULL") it is no longer needed to set the wait_prepare/finish
vb2_ops callbacks as long as the lock field in vb2_queue is set.

Since the vb2_ops_wait_prepare/finish callbacks already rely on that field,
we can safely drop these callbacks.

This simplifies the code and this is a step towards the goal of deleting
these callbacks.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Link: https://lore.kernel.org/r/2fb746b8-31c4-44e0-bf7b-7a0758edf52a@xs4all.nl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/uvc_queue.c

@@ -122,8 +122,6 @@ static const struct vb2_ops uvc_queue_qops = {
 	.queue_setup = uvc_queue_setup,
 	.buf_prepare = uvc_buffer_prepare,
 	.buf_queue = uvc_buffer_queue,
-	.wait_prepare = vb2_ops_wait_prepare,
-	.wait_finish = vb2_ops_wait_finish,
 };
 
 int uvcg_queue_init(struct uvc_video_queue *queue, struct device *dev, enum v4l2_buf_type type,