Revert "Revert "drm/i810: cleanup reclaim_buffers""

Revert "Revert "drm/i810: cleanup reclaim_buffers""

This reverts commit ad1ebb359071c2ca6dc57231d07adecb27faeffc,
reinstating the original commit:

commit cb41c23e5d88ac06ba83f1bc7f2ec018a2b74e9f
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Oct 25 23:51:24 2011 +0200

    drm/i810: cleanup reclaim_buffers

    My dear old i815 always hits the deadlocked on reclaim_buffers
    warning. Switch over to the idlelock duct-tape on hope that
    works better. I've fired up my i815 and now closing glxgears doesn't
    take 5 seconds anymore. \o/

The original problem with that was that I've moved it ahead in the
series so that it could be included despite some patches not being
ready quite yet. The little problem is that this patch required some
of the previous rework to work correctly.

Now that everything is in the right order again, this actually works
on my i810 and does speed up closing gl apps as the original commit
claimed. Without hanging the machine, as the revert says.

Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>