[LEDE-DEV] [LEDE-DEV, 2/3, v2] Add support of using device symlinks.

[Nikolay Ledovskikh]

> still pending not had time to look into this. it'll take me a moment as
> i am not familiar with the code so i need to find a free moment to
> properly review this, sorry for the delay
>
>         John

OK. I just offer to use 'readlink' onto 'device', so as a result we
always get a real device if it were symlink or not.