media: atomisp: split add from find subdev

There's only one place where a subdev can be added: when the
sensor driver registers it. Trying to do it elsewhere will
cause problems, as the detection code needs to access the
I2C bus in order to probe some things.
Tested-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c

@@ -202,6 +202,8 @@ int atomisp_register_i2c_module(struct v4l2_subdev *subdev,
 	 * gmin_subdev struct is already initialized for us.
 	 */
 	gs = find_gmin_subdev(subdev);
+	if (!gs)
+		return -ENODEV;
 
 	pdata.subdevs[i].type = type;
 	pdata.subdevs[i].port = gs->csi_port;
@@ -713,7 +715,7 @@ static struct gmin_subdev *find_gmin_subdev(struct v4l2_subdev *subdev)
 	for (i = 0; i < MAX_SUBDEVS; i++)
 		if (gmin_subdevs[i].subdev == subdev)
 			return &gmin_subdevs[i];
-	return gmin_subdev_add(subdev);
+	return NULL;
 }
 
 static int axp_regulator_set(struct device *dev, struct gmin_subdev *gs,
@@ -1064,7 +1066,7 @@ struct camera_sensor_platform_data *gmin_camera_platform_data(
     enum atomisp_input_format csi_format,
     enum atomisp_bayer_order csi_bayer)
 {
-	struct gmin_subdev *gs = find_gmin_subdev(subdev);
+	struct gmin_subdev *gs = gmin_subdev_add(subdev);
 
 	gs->csi_fmt = csi_format;
 	gs->csi_bayer = csi_bayer;