[RFC] ttm merge move/move_notify/invalidate_caches callback

[j.glisse@gmail.com]

This was discussed previously :
http://lists.freedesktop.org/archives/dri-devel/2012-January/018463.html

The plat de resistance is in patch4, the first 3 are simplification that
i believe can go as is.

Idea is that driver needs to know when ever a bo move happen and instead
of having 3 set of callback to allow driver to do things btw common ttm
move handling. Move the ttm move handling into each driver and let driver
customize it at appropriate point.

I intentionaly didn't not fully take advantage of that in neither radeon
or nouveau. ie i tried to keep the current code as much as possible so
one can see that i don't disrupt old behavior. There is opportunity to
simplify the move_notify driver function i believe.

I tested it on radeon and nouveau. This time i limited the 2G vram nvidia
gpu i have to behave like a 64M vram or 96M vram so i actually see the
vram eviction path being exercice while testing (this is why in my last
ttm patch set i missed the nouveau regression, again sorry about that).
So i am more confident that with this one i didn't regressed anything.

Thomas i tried to be carefull with vmwgfx but i didn't tested it. Only
built tested.

Cheers,
Jerome