Merge "devfreq: bw_mon: check for the return value of start_monitor"

/*

 * Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.

 * Copyright (c) 2013-2019, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

	node->orig_data = df->data;

	df->data = node;

	if (start_monitor(df, true))

	ret = start_monitor(df, true);

	if (ret)

		goto err_start;

	ret = sysfs_create_group(&df->dev.kobj, node->attr_grp);