Unbreak build after #621 (#826)

Author: andrewor14

torchao/dtypes/affine_quantized_tensor.py

@@ -1,6 +1,5 @@
 import torch
 from typing import Tuple, Optional, Union
-import torchao.ops
 from collections import defaultdict
 import functools
 import math
@@ -1425,6 +1424,8 @@ def _linear_fp_act_int4_weight_sparse_marlin_check(input_tensor, weight_tensor,
 
 def _linear_fp_act_int4_weight_sparse_marlin_impl(input_tensor, weight_tensor, bias):
     from torchao.sparsity.marlin import marlin_24_workspace, const
+    from torchao.ops import marlin_24_gemm
+
     assert isinstance(weight_tensor, AffineQuantizedTensor)
 
     sparse_w_int4 = weight_tensor.layout_tensor.int_data
@@ -1441,7 +1442,7 @@ def _linear_fp_act_int4_weight_sparse_marlin_impl(input_tensor, weight_tensor, b
     size_k = input_2d.shape[1]
     workspace_24 = marlin_24_workspace(original_shape[1])
 
-    out = torchao.ops.marlin_24_gemm(
+    out = marlin_24_gemm(
         input_2d, sparse_w_int4, meta, scale, 
         workspace_24, num_bits, size_m, size_n, size_k
     )