Fix typo in VLLM_TPU_USING_PATHWAYS flag (#1074)

Signed-off-by: Richard Liu <ricliu@google.com>

Author: richardsliu

tpu_inference/layers/vllm/sharding.py

@@ -84,7 +84,7 @@ def _tensor_is_in_cpu(tensor: torch.tensor) -> bool:
 
 def _convert_to_torchax_and_shard(tensor: torch.Tensor,
                                   sharding: NamedSharding) -> torch.Tensor:
-    if os.getenv("VLLM_TPU_USE_PATHWAYS", False) and tensor is torch.Tensor:
+    if os.getenv("VLLM_TPU_USING_PATHWAYS", False) and tensor is torch.Tensor:
         np_tensor = tensor.detach().cpu().to(torch.float32).numpy()
         dtype = TORCH_TO_JAX_DTYPE_MAP.get(tensor.dtype, jnp.float32)
         return torch_view(jax.device_put(np_tensor, sharding).astype(dtype))