This fixes a bug in the CLUSTER_BROADCAST code generation that causes
the original IR region to be ignored, this will be a problem when we
start lowering 64-bit CLUSTER_BROADCAST instructions at the IR level,
since it will lead to instructions with non-trivial regioning.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14273>