media: v4l2-ctrls: return -EACCES if request wasn't completed

An attempt to call :ref:`VIDIOC_S_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` for a

request that has already been queued will result in an ``EBUSY`` error.

If ``request_fd`` is specified and ``which`` is set to ``V4L2_CTRL_WHICH_REQUEST_VAL``

during a call to :ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>`, then the

returned values will be the values currently set for the request (or the

hardware value if none is set) if the request has not yet been queued, or the

values of the controls at the time of request completion if it has already

completed. Attempting to get controls while the request has been queued but

not yet completed will result in an ``EBUSY`` error.

If ``request_fd`` is specified and ``which`` is set to

``V4L2_CTRL_WHICH_REQUEST_VAL`` during a call to

:ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>`, then it will return the

values of the controls at the time of request completion.

If the request is not yet completed, then this will result in an

``EACCES`` error.

The driver will only set/get these controls if all control values are

correct. This prevents the situation where only some of the controls

    and this error code is returned.

EACCES

    Attempt to try or set a read-only control or to get a write-only

    control.

    Attempt to try or set a read-only control, or to get a write-only

    control, or to get a control from a request that has not yet been

    completed.

EPERM

    The ``which`` field was set to ``V4L2_CTRL_WHICH_REQUEST_VAL`` but the

		if (IS_ERR(req))

			return PTR_ERR(req);

		if (req->state != MEDIA_REQUEST_STATE_IDLE &&

		    req->state != MEDIA_REQUEST_STATE_COMPLETE) {

		if (req->state != MEDIA_REQUEST_STATE_COMPLETE) {

			media_request_put(req);

			return -EBUSY;

			return -EACCES;

		}

		obj = v4l2_ctrls_find_req_obj(hdl, req, false);