My PIPE_CONTROL fix (just sent via Eric's tree) was buggy; I was
testing a whole set of patches together and missed a conversion to the
new HAS_PIPE_CONTROL macro, which will cause breakage on non-Ironlake
965 class chips. Fortunately, the fix is trivial and has been tested.
Be sure to use the HAS_PIPE_CONTROL macro in i915_get_gem_seqno, or
we'll end up reading the wrong graphics memory, likely causing hangs,
crashes, or worse.