intel/brw: Skip fs_nir_setup_outputs for compute shaders

There aren't any outputs, so there's no point to doing this work.

Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29624>

src/intel/compiler/brw_fs_nir.cpp

@@ -135,7 +135,8 @@ fs_nir_setup_outputs(nir_to_brw_state &ntb)
    if (s.stage == MESA_SHADER_TESS_CTRL ||
        s.stage == MESA_SHADER_TASK ||
        s.stage == MESA_SHADER_MESH ||
-       s.stage == MESA_SHADER_FRAGMENT)
+       s.stage == MESA_SHADER_FRAGMENT ||
+       s.stage == MESA_SHADER_COMPUTE)
       return;
 
    unsigned vec4s[VARYING_SLOT_TESS_MAX] = { 0, };