message: fix emb under int8 autocast
diff: @@ -404,7 +404,10 @@ at::Tensor embedding_bag(
  #if defined(ENABLE_AUTOCAST_VERBOSE)
  verbose::OpNameGuard op_name("embedding_bag");
  #endif
  - auto casted_weight = at::GradMode::is_enabled() ? weight : cpu_cached_cast(at::kBFloat16, weight);
  + auto target_type = get_autocast_dtype();
  + // only have bf16 support now, keep fp32 for other target_type
  + bool cast_to_bfloat16 = !at::GradMode::is_enabled() && at::kBFloat16 == target_type;
  + auto casted_weight = cast_to_bfloat16 ? cpu_cached_cast(at::kBFloat16, weight) : weight;
  return op.call(casted_weight, indices, offsets, sparse, include_last_offset);
  }
  