gallium: astc 3D format definitions
Continuing my format enum unification attempt, I've been looking at what it would look like to have
MESA_FORMAT_* defined in terms of gallium formats. The biggest gap is the lack of ASTC 3D
PIPE_FORMAT_* enums. Those are easy enough to bring over, and surely someone (AMD? Looks like they've got some reg definitions) is going to want it.