ac,radeonsi: many improvements around the whole driver, some perf improvements
Some interesting stuff here:
- Enable DCC fast clear for 8bpp and 16bpp on GFX11
- New fast clear method for GFX11: DCC clear-to-single (based on RADV)
- Gfx blits preserve NaNs
- Disable VRS 2x2 for flat shading when it decreases performance of slow gfx clears
- Skip no-op CB and DB cache flushes
- Many cosmetic changes around blits and clears.
The NIR commit is from !28606 (merged).
This is a prerequisite for the future compute blit.