fixed below checkpatch warnings.
- WARNING: Prefer netdev_err(netdev, ... then dev_err(dev, ... then pr_err(... to printk(KERN_ERR ...
- WARNING: Prefer netdev_info(netdev, ... then dev_info(dev, ... then pr_info(... to printk(KERN_INFO ...
- WARNING: Prefer netdev_notice(netdev, ... then dev_notice(dev, ... then pr_notice(... to printk(KERN_NOTICE ...