media: imx7-mipi-csis: remove subdev_notifier

It was defined a notifier in the csi_state structure that is never
allocated. And besides that it's unregister in the remove, even though
it is a no-op, just remove both.

Fixes: 7807063b ("media: staging/imx7: add MIPI CSI-2 receiver subdev for i.MX7")
Reported-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Reviewed-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/imx/imx7-mipi-csis.c

@@ -251,8 +251,6 @@ struct csi_state {
 
 	struct mipi_csis_event events[MIPI_CSIS_NUM_EVENTS];
 
-	struct v4l2_async_notifier subdev_notifier;
-
 	struct csis_hw_reset hw_reset;
 	struct regulator *mipi_phy_regulator;
 	bool sink_linked;
@@ -1104,7 +1102,6 @@ static int mipi_csis_remove(struct platform_device *pdev)
 
 	mipi_csis_debugfs_exit(state);
 	v4l2_async_unregister_subdev(&state->mipi_sd);
-	v4l2_async_notifier_unregister(&state->subdev_notifier);
 
 	pm_runtime_disable(&pdev->dev);
 	mipi_csis_pm_suspend(&pdev->dev, true);