USB: chipidea: convert platform driver to use dev_groups

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" any sysfs files.

Cc: Peter Chen <Peter.Chen@nxp.com>
Link: https://lore.kernel.org/r/20190805193636.25560-1-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/core.c

@@ -903,10 +903,7 @@ static struct attribute *ci_attrs[] = {
 	&dev_attr_role.attr,
 	NULL,
 };
-
-static const struct attribute_group ci_attr_group = {
-	.attrs = ci_attrs,
-};
+ATTRIBUTE_GROUPS(ci);
 
 static int ci_hdrc_probe(struct platform_device *pdev)
 {
@@ -1105,14 +1102,8 @@ static int ci_hdrc_probe(struct platform_device *pdev)
 	device_set_wakeup_capable(&pdev->dev, true);
 	dbg_create_files(ci);
 
-	ret = sysfs_create_group(&dev->kobj, &ci_attr_group);
-	if (ret)
-		goto remove_debug;
-
 	return 0;
 
-remove_debug:
-	dbg_remove_files(ci);
 stop:
 	if (ci->is_otg && ci->roles[CI_ROLE_GADGET])
 		ci_hdrc_otg_destroy(ci);
@@ -1139,7 +1130,6 @@ static int ci_hdrc_remove(struct platform_device *pdev)
 	}
 
 	dbg_remove_files(ci);
-	sysfs_remove_group(&ci->dev->kobj, &ci_attr_group);
 	ci_role_destroy(ci);
 	ci_hdrc_enter_lpm(ci, true);
 	ci_usb_phy_exit(ci);
@@ -1318,6 +1308,7 @@ static struct platform_driver ci_hdrc_driver = {
 	.driver	= {
 		.name	= "ci_hdrc",
 		.pm	= &ci_pm_ops,
+		.dev_groups = ci_groups,
 	},
 };