radeonsi: implement and use compute-based DCC decompression on gfx9-10

DCC_DECOMPRESS doesn't work. Instead of trying to figure out why,
use a compute blit where the load is compressed and the store is
uncompressed.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4761>
7 files changed