fix: Remove unused dequantize_nvfp4 import in LinearNVFP4

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: TimDettmers

bitsandbytes/nn/modules.py

@@ -718,7 +718,7 @@ def forward(self, x: torch.Tensor) -> torch.Tensor:
         if not self.weight_quantized:
             self._quantize_weight()
 
-        from bitsandbytes.functional import dequantize_nvfp4, gemm_nvfp4, quantize_nvfp4
+        from bitsandbytes.functional import gemm_nvfp4, quantize_nvfp4
 
         inp_dtype = x.dtype
         input_shape = x.shape