intel/compiler: remove second shading rate lowering for mesh

It's already called in brw_postprocess_nir and calling it the second time
actually breaks shading rate.

Initially, when I added this call here in 9acb30c8c4, I was testing it
on an internal tree, which didn't have brw_nir_lower_shading_rate_output call
in brw_postprocess_nir.

Fixes: 9acb30c8c4 ("intel/compiler: implement primitive shading rate for mesh")
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18702>

src/intel/compiler/brw_mesh.cpp

@@ -530,8 +530,6 @@ brw_nir_lower_mue_outputs(nir_shader *nir, const struct brw_mue_map *map)
 
    NIR_PASS(_, nir, nir_lower_io, nir_var_shader_out,
             type_size_scalar_dwords, nir_lower_io_lower_64bit_to_32);
-
-   NIR_PASS(_, nir, brw_nir_lower_shading_rate_output);
 }
 
 static void