[coreboot] [RFC] Drop PowerPC port

[Stefan Reinauer]

Uwe Hermann wrote:
>> We should probably try to have a "last known working version"
>> in the supported boards list on the wiki.
>>     
>
> Hm, dunno, if the boards are removed from svn we could also remove them from
> the wiki table completely (or put them in a "supported in earlier revisions"
> table somewhere else, in case somebody may want to resurrect them).
>   

Good idea. We might want to put the v1 and v3 only boards there, too..