Radeon MC setup cleanup

[Benjamin Herrenschmidt]

> I haven't followed the whole discussion... but there is definitely a
> need to save/restore the memmap for things like suspend/resume, and
> interaction with a few other things (though at this stage I would hope
> radeonfb not to change the memmap, but instead adapt to the change done
> by X, though that is to be tested).

I also remember a reason why the code is the way it is ... With some
version of the DRM, the later would muck around the memory map in
incorrect ways and the code in the server was working around it.

Cheers,
Ben.