drm/i915: Enable RC6 on Ironlake.

RC6 allows the GPU to enter a lower power state when the GPU is idle.

Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
[anholt: Fixed the !renderctx error path to actually not enable RC6.]
Signed-off-by: Eric Anholt <eric@anholt.net>
1 file changed