media: ipu3-cio2: Remove traces of returned buffers

If starting a video buffer queue fails, the buffers are returned to
videobuf2. Remove the reference to the buffer from the driver's queue as
well.

Fixes: c2a6a07afe ("media: intel-ipu3: cio2: add new MIPI-CSI2 driver")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: stable@vger.kernel.org # v4.16 and up
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/pci/intel/ipu3/ipu3-cio2.c

@@ -791,6 +791,7 @@ static void cio2_vb2_return_all_buffers(struct cio2_queue *q,
 			atomic_dec(&q->bufs_queued);
 			vb2_buffer_done(&q->bufs[i]->vbb.vb2_buf,
 					state);
+			q->bufs[i] = NULL;
 		}
 	}
 }