linux: Disable rc6 only for Sandybridge GT1 gpus to not influence power saving on Ivybridge and others
Projects: Reenable rc6 gt1 by default with snb gt1 now blacklisted
Merge pull request #2335 from fritsch/rc6-disable-intel-snb-gt1

Only disable RC6 on Sandybridge GT1 and not on all intel hardware