No more drm_*_agp in i915_gem.c!
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

This still uses the agp functions to actually reinstate the mappings
(with a gross hack to make agp cooperate), but it wires everything
up correctly for the switchover.

The call to agp_rebind_memory can be dropped because all non-kms drivers
do all their rebinding on EnterVT.

v2: Be more paranoid and flush the chipset cache after restoring gtt
mappings.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

Now that the drm core can do this, lets just use it, split the code out
so TTM doesn't have to drag all of drmP.h in.
Signed-off-by: NDave Airlie <airlied@redhat.com>