nak/lower_tex: Don't use remap_sampler_dim() for images

Subpass images should only ever show up as textures thanks to
nir_lower_input_attachments().  Also, you can't do imageSize() on an
input attachment anyway.

Reviewed-by: Mary Guillemard <mary.guillemard@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36207>

src/nouveau/compiler/nak_nir_lower_tex.c

@@ -594,7 +594,7 @@ lower_image_txq(nir_builder *b, nir_intrinsic_instr *intrin,
    }
 
    nir_tex_instr *txq = nir_tex_instr_create(b->shader, 1);
-   txq->sampler_dim = remap_sampler_dim(nir_intrinsic_image_dim(intrin));
+   txq->sampler_dim = nir_intrinsic_image_dim(intrin);
    txq->is_array = nir_intrinsic_image_array(intrin);
    txq->dest_type = nir_type_int32;