[Xorg] New XAA Render hooks

[Eric Anholt]

http://www.freedesktop.org/~anholt/xorg-renderhooks.diff

Here's a patch for the new Render hooks and support for them on Radeon. 
More information is in the ChangeLog diff at the top.  Note that this
causes all other render accelerations using XAA to become disabled until
those drivers get fixed.

I really want to see us have the cleanest Render support we can in this
release, which is why I'm disabling old support even though it might
seem to "just work" for others currently.  I know we've got some
outstanding issues in software fallbacks, unfortunately.

This extends the XAAInfoRec.  What's the proper way for dealing with
extending that, in terms of module ABI?

-- 
Eric Anholt                                eta at lclark.edu          
http://people.freebsd.org/~anholt/         anholt at FreeBSD.org