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

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

This reverts commit 6e877b576ddf7cde5db2e9a6dcb56fef0ea77e64,
reinstating the original commit:

commit 87499ffdcb1c70f66988cd8febc4ead0ba2f9118
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>