rtl8723ds: fix rtnl_lock handling

[johnkeeping]

The important commit here fixes the locking in rtw_os_ndev_register() and rtw_os_ndev_unregister(); the other commit is just removing an unnecessary check since we're guaranteed to already hold rtnl_lock.

For registration, I have seen cases where register_netdevice() is being called without holding rtnl_lock because it is being held by another task and this breaks all the locking requirements.

[lwfinger]

Merged. Thanks.

[johnkeeping]

I'm not seeing this on master - did something go wrong with the merge?

[lwfinger]

I have no idea what went wrong. It is merged now.