samples: configfs: prefer pr_err() over bare printk(KERN_ERR

pr_*() printing helpers are preferred over using bare printk().
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

samples/configfs/configfs_sample.c

@@ -341,9 +341,8 @@ static int __init configfs_example_init(void)
 		mutex_init(&subsys->su_mutex);
 		ret = configfs_register_subsystem(subsys);
 		if (ret) {
-			printk(KERN_ERR "Error %d while registering subsystem %s\n",
-			       ret,
-			       subsys->su_group.cg_item.ci_namebuf);
+			pr_err("Error %d while registering subsystem %s\n",
+			       ret, subsys->su_group.cg_item.ci_namebuf);
 			goto out_unregister;
 		}
 	}