[media] sh_mobile_csi2: fix module reloading

If the camera host driver (sh_mobile_ceu_camera.c) is unloaded and then
reloaded, probe will fail, because camera client .set_bus_param() and
.query_bus_param() methods have been set to NULL. Fix this by caching
the original pointers and restoring them on driver-unbind.

Signed-off-by: Guennadi Liakhovetski <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/sh_mobile_csi2.c

···
 	void __iomem			*base;
 	struct platform_device		*pdev;
 	struct sh_csi2_client_config	*client;
+	unsigned long (*query_bus_param)(struct soc_camera_device *);
+	int (*set_bus_param)(struct soc_camera_device *, unsigned long);
 };
 
 static int sh_csi2_try_fmt(struct v4l2_subdev *sd,
···
 
 		priv->client = pdata->clients + i;
 
+		priv->set_bus_param		= icd->ops->set_bus_param;
+		priv->query_bus_param		= icd->ops->query_bus_param;
 		icd->ops->set_bus_param		= sh_csi2_set_bus_param;
 		icd->ops->query_bus_param	= sh_csi2_query_bus_param;
 
···
 		priv->client = NULL;
 
 		/* Driver is about to be unbound */
-		icd->ops->set_bus_param		= NULL;
-		icd->ops->query_bus_param	= NULL;
+		icd->ops->set_bus_param		= priv->set_bus_param;
+		icd->ops->query_bus_param	= priv->query_bus_param;
+		priv->set_bus_param		= NULL;
+		priv->query_bus_param		= NULL;
 
 		v4l2_device_unregister_subdev(&priv->subdev);