nir/lower_system_values: add ID to 32-bit lowering
What does this MR do and why?
nir/lower_system_values: add ID to 32-bit lowering
OpenCL has 64-bit global IDs, but for driver-internal OpenCL we only need
32-bit. Might as well lower in nir_lower_system_values instead of bringing up a
whole new pass just for this.
Will be used for asahi precomp
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>