remove transformer interface

hyperparams.yaml

@@ -122,13 +122,10 @@ tokenizer: !new:sentencepiece.SentencePieceProcessor
 asr_model: !new:torch.nn.ModuleList
     - [!ref <CNN>, !ref <Transformer>, !ref <seq_lin>, !ref <ctc_lin>]
 
-asr_encoder: !new:speechbrain.nnet.containers.Sequential
-    - !ref <CNN>
-    - !ref <Transformer.encode>
-
 modules:
    compute_features: !ref <compute_features>
-   asr_encoder: !ref <asr_encoder>
+   pre_transformer: !ref <CNN>
+   transformer: !ref <Transformer>
    asr_model: !ref <asr_model>
    normalize: !ref <normalize>
    lm_model: !ref <lm_model>