radv: Initial displayable DCC support.
Initial support, generally has a small speedup or same perf.
Future work (out of scope for initial MR):
- Modifier support. For this I need to deal with the extra bools in general and ensure we never ask for extra memory.
- Optimized retiling & retile memory management. The current management is kinda naive and I think there are big wins in how we can write the shader.
- Less overhead with overlays. Overlays typically transition back from the present layout, render and then back to present layout so we do the retile twice. See if we can avoid 1 of those at not too much CPU cost.