[coreboot] Update on G505S (dGPU init success)

[awokd]

Hans Jürgen Kitter:
>   Hi All,
> 
> I thought that I share with the G505S+Coreboot (+QubesOS) users that I
> finally managed to enable and use the dGPUs on the G505S boards.
Nice hacking! I know Mike Banon was working with some others on this 
too, hopefully you were able to compare notes. Any benefits to G505s 
owners who don't have the secondary GPU?