FIX TST Wrong attribute in LoftQ test (#2841)

This is to fix an oversight from #2797, where the LoftQ test was
sligthly refactored but one test was not updated accordingly.

Author: BenjaminBossan

tests/test_gpu_examples.py

@@ -2950,8 +2950,9 @@ def test_bloomz_loftq_4bit(self, device, tmp_path):
         assert mse_loftq > 0.0
 
         # next, check that LoftQ quantization errors are smaller than LoRA errors by a certain margin
-        assert mse_loftq < (mse_quantized / self.error_factor)
-        assert mae_loftq < (mae_quantized / self.error_factor)
+        error_factor = self.get_error_factor(device)
+        assert mse_loftq < (mse_quantized / error_factor)
+        assert mae_loftq < (mae_quantized / error_factor)
 
     @pytest.mark.parametrize("device", [torch_device, "cpu"])
     def test_bloomz_loftq_4bit_iter_5(self, device, tmp_path):