Revert "net-sysfs: Fix memory leak in netdev_register_kobject"

This reverts commit 6b70fc94.

The reverted bugfix will cause another issue.
Reported by syzbot+6024817a931b2830bc93@syzkaller.appspotmail.com.
See https://syzkaller.appspot.com/x/log.txt?x=1737671b200000

 for
details.

Signed-off-by: Wang Hai <wanghai26@huawei.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>