fix bug

Co-authored-by: Yi30 <106061964+yiliu30@users.noreply.github.com>

Author: xin3he

test/3x/torch/test_config.py

@@ -57,7 +57,7 @@ def test_quantize_rtn_from_dict_beginner(self):
         from neural_compressor.torch import quantize
 
         quant_config = {
-            "RTN": {
+            "rtn": {
                 "weight_dtype": "nf4",
                 "weight_bits": 4,
                 "weight_group_size": 32,