treewide: Stop lowering legacy atomics

There are no more producers of legacy atomics so these calls are inert.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23036>

src/intel/compiler/brw_nir.c

@@ -932,8 +932,6 @@ brw_preprocess_nir(const struct brw_compiler *compiler, nir_shader *nir,
 
    OPT(nir_lower_frexp);
 
-   OPT(nir_lower_legacy_atomics);
-
    if (is_scalar) {
       OPT(nir_lower_alu_to_scalar, NULL, NULL);
    }