hwmon: (ds1621) Use kobj_to_dev()

fixed the following coccicheck:
./drivers/hwmon/ds1621.c:329:60-61: WARNING opportunity
for kobj_to_dev().
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Link: https://lore.kernel.org/r/1616032504-59817-1-git-send-email-tiantao6@hisilicon.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/ds1621.c

@@ -326,7 +326,7 @@ static struct attribute *ds1621_attributes[] = {
 static umode_t ds1621_attribute_visible(struct kobject *kobj,
 					struct attribute *attr, int index)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct ds1621_data *data = dev_get_drvdata(dev);
 
 	if (attr == &dev_attr_update_interval.attr)