drm/i915/guc: Add GuC ADS - enabling ADS

Set ADS enabling flag during GuC init.

Signed-off-by: Alex Dai <yu.dai@intel.com>
Reviewed-by: Dave Gordon <david.s.gordon@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450468812-4882-6-git-send-email-yu.dai@intel.com


Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>