Textures that likely reside in VRAM, are mapped for reading and
don't require direct mapping should be staged into GTT, to avoid bad
performance. This fixes readback performance of VDPAU surfaces.
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
The function r600_choose_tiling is new and needs a review.
The only change in functionality is that it enables 2D tiling for compressed
textures on SI. It was probably accidentally turned off.
v2: don't make scanout buffers linear