[Mesa-dev] [rfc] radv 32 descriptor set support

[Dave Airlie]

amdgpu-pro advertise 32 bound descriptor sets, and we have some
possible workloads that might need more than 4.

This series add a little pre-pass to gather some radv specific info
(there are more things I want to use this for), then add support
indirect binding of the descriptor sets via a lookup buffer that
is shared amongst all the shaders.

I've only tested this by forcing on the indirect path for all shaders,
since I've got no workloads to actually make it happen yet, and CTS
doesn't appear to tickle much in this area.

This is also a precursor for inlining push constants into user sgprs.

Dave.