drm/i915: Allow large objects to be tiled on gen2/3

drm/i915: Allow large objects to be tiled on gen2/3

We now have partial VMA support to break large objects into fence sized
regions and no longer have to restrict tiling to small objects on gen2/3

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170203115036.24743-2-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>