media: ad5820: Define entity function

Without this patch, media_device_register_entity throws a warning:

dev_warn(mdev->dev,
	 "Entity type for entity %s was not initialized!\n",
	 entity->name);
Signed-off-by: Ricardo Ribalda Delgado <ribalda@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/i2c/ad5820.c

@@ -309,6 +309,7 @@ static int ad5820_probe(struct i2c_client *client,
 	v4l2_i2c_subdev_init(&coil->subdev, client, &ad5820_ops);
 	coil->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
 	coil->subdev.internal_ops = &ad5820_internal_ops;
+	coil->subdev.entity.function = MEDIA_ENT_F_LENS;
 	strscpy(coil->subdev.name, "ad5820 focus", sizeof(coil->subdev.name));
 
 	ret = media_entity_pads_init(&coil->subdev.entity, 0, NULL);