mfd: lm3533: Switch to using the new API kobj_to_dev()

Fixes the following coccicheck warning:

  drivers/mfd/lm3533-core.c:361:60-61: WARNING opportunity for kobj_to_dev()
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/lm3533-core.c

@@ -358,7 +358,7 @@ static struct attribute *lm3533_attributes[] = {
 static umode_t lm3533_attr_is_visible(struct kobject *kobj,
 					     struct attribute *attr, int n)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct lm3533 *lm3533 = dev_get_drvdata(dev);
 	struct device_attribute *dattr = to_dev_attr(attr);
 	struct lm3533_device_attribute *lattr = to_lm3533_dev_attr(dattr);