intel/fs: Drop support for nir_register

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24104>

src/intel/compiler/brw_fs_visitor.cpp

@@ -1410,7 +1410,6 @@ fs_visitor::init()
    this->failed = false;
    this->fail_msg = NULL;
 
-   this->nir_locals = NULL;
    this->nir_ssa_values = NULL;
    this->nir_resource_insts = NULL;
    this->nir_ssa_bind_infos = NULL;