intel_th: pti: Create sysfs attributes using core driver's facility

The core intel_th driver allows subdevices to bring in their sysfs
attributes. Use this instead of taking care of them in probe and
remove.

Signed-off-by: Alexander Shishkin <[e-mail]>
Reviewed-by: Laurent Fert <[e-mail]>

drivers/hwtracing/intel_th/pti.c

···
 	struct resource *res;
 	struct pti_device *pti;
 	void __iomem *base;
-	int ret;
 
 	res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
 	if (!res)
···
 
 	read_hw_config(pti);
 
-	ret = sysfs_create_group(&dev->kobj, &pti_output_group);
-	if (ret)
-		return ret;
-
 	dev_set_drvdata(dev, pti);
 
 	return 0;
···
 
 static void intel_th_pti_remove(struct intel_th_device *thdev)
 {
-	sysfs_remove_group(&thdev->dev.kobj, &pti_output_group);
 }
 
 static struct intel_th_driver intel_th_pti_driver = {
···
 	.remove	= intel_th_pti_remove,
 	.activate	= intel_th_pti_activate,
 	.deactivate	= intel_th_pti_deactivate,
+	.attr_group	= &pti_output_group,
 	.driver	= {
 		.name	= "pti",
 		.owner	= THIS_MODULE,