mesa/ati_fs: Move sampler dim adjustment to a separate NIR pass.

This means that the main NIR translation for ATI_fs is now independent of
the fp key, and we could do it earlier in the compile pipeline.

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23111>

src/mesa/state_tracker/st_program.c

@@ -926,6 +926,9 @@ st_create_fp_variant(struct st_context *st,
             true, false);
          nir_lower_global_vars_to_local(state.ir.nir);
       }
+
+      NIR_PASS_V(state.ir.nir, st_nir_lower_atifs_samplers, key->texture_index);
+
       finalize = true;
    }