Use the same URB access helpers that were added for Task Output. The
Arrayed I/O (per-primitive and per-vertex) is handled by applying the
pitch from the MUE layout into the NIR intrinsics and including the
non-arrayed offset on top of it. After that, the index src can be
used directly for lowering.
Because we keep around the non-arrayed offset AND the pitch is
aligned, we can identify cases where the access is indirect but
guaranteed to be aligned, and dispatch a single message. Added a TODO
to explore that later.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13661>