This removes the use of fake buffers from the driver, such that it could
probably be removed from the interface. It also should assist in proper
synchronization of access.
Now, allocations only take locations, rather than a variety of unused flags.
The only interesting flag before was the no_move/no_evict pair for scanout
and similar buffers, which the DRI drivers don't use. That will be readded
when we get to using this code for display buffer allocation, by adding a
pin/unpin call (dynamic pinning/unpinning may be useful for VT switching and
root window resizing).
This commit changes one instance of DRM_BO_FLAG_MEM_LOCAL with
DRM_BO_FLAG_MEM_TT, which appeared to have been unintentional.
The interface is not solid yet (some simplification to do still, and
adjustment for 0-copy), and the drivers are not converted. However, the new
interface allows using the same calls to support either a TTM or a classic
static allocation backend, with the static backend allowing a more limited
feature set.
