The early commit is done to facilitate the off-tree work on the
porting of the Radeon driver.
Sponsored by: The FreeBSD Foundation
Debugged and tested by: dumbbell
MFC after: 1 month
works with new generations of GPUs (IronLake, SandyBridge and
supposedly IvyBridge).
The driver is not connected to the build yet.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week