pwm: sysfs: Convert to use ATTRIBUTE_GROUPS macro

Use new ATTRIBUTE_GROUPS macro to reduce the number of lines of code.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

drivers/pwm/sysfs.c

@@ -169,15 +169,7 @@ static struct attribute *pwm_attrs[] = {
 	&dev_attr_polarity.attr,
 	NULL
 };
-
-static const struct attribute_group pwm_attr_group = {
-	.attrs		= pwm_attrs,
-};
-
-static const struct attribute_group *pwm_attr_groups[] = {
-	&pwm_attr_group,
-	NULL,
-};
+ATTRIBUTE_GROUPS(pwm);
 
 static void pwm_export_release(struct device *child)
 {
@@ -205,7 +197,7 @@ static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
 	export->child.release = pwm_export_release;
 	export->child.parent = parent;
 	export->child.devt = MKDEV(0, 0);
-	export->child.groups = pwm_attr_groups;
+	export->child.groups = pwm_groups;
 	dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
 
 	ret = device_register(&export->child);