nir: Add intrinsics for object to/from world RT sysvals

These are a bit more tricky than most because they're matrix system
values.  We make the intentional choice here to not bother with allowing
indirect addressing of columns for these.  Since they're system values,
they may be magically constructed somehow or come from weird hardware so
it's easier on back-ends to just handle any indirects with bcsel.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6479>
5 files changed