The code using this was removed in:

  commit 88f23b8f
  Author: Chris Wilson <chris@chris-wilson.co.uk>
  Date:   Sun Dec 5 15:08:31 2010 +0000

      drm/i915: Avoid using PIPE_CONTROL on Ironlake
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>