drm/i915: Align "unfenced" tiled access on gen2, early gen3

Old devices have quite severe restrictions for using fences, and unlike
more recent device (anything from Pineview onwards) we need to enforce
those restrictions even for unfenced tiled access from the render
pipeline.

Fixes: 944397f0

 ("drm/i915: Store required fence size/alignment for GGTT vma")
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.11-rc1+
Link: http://patchwork.freedesktop.org/patch/msgid/20170325113243.16438-1-chris@chris-wilson.co.uk


Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>