USB: Fix debugfs_create_file's error checking method for usb/gadget/s3c2410_udc

debugfs_create_file() returns NULL if an error occurs, returns -ENODEV
when debugfs is not enabled in the kernel.
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/s3c2410_udc.c

@@ -1894,11 +1894,8 @@ static int s3c2410_udc_probe(struct platform_device *pdev)
 		udc->regs_info = debugfs_create_file("registers", S_IRUGO,
 				s3c2410_udc_debugfs_root,
 				udc, &s3c2410_udc_debugfs_fops);
-		if (IS_ERR(udc->regs_info)) {
-			dev_warn(dev, "debugfs file creation failed %ld\n",
-				 PTR_ERR(udc->regs_info));
-			udc->regs_info = NULL;
-		}
+		if (!udc->regs_info)
+			dev_warn(dev, "debugfs file creation failed\n");
 	}
 
 	dev_dbg(dev, "probe ok\n");