Fix bugs of s2t fairseq model converting (#15593)

* Fix bugs for argument typo and positional embedding weight loading

* Reflect code review suggestion to cover different missing keys cases

src/transformers/models/speech_to_text/convert_s2t_fairseq_to_tfms.py

@@ -94,7 +94,17 @@ def convert_fairseq_s2t_checkpoint_to_tfms(checkpoint_path, pytorch_dump_folder_
     )
 
     model = Speech2TextForConditionalGeneration(config)
-    model.model.load_state_dict(state_dict)
+    missing, unexpected = model.model.load_state_dict(state_dict, strict=False)
+    if len(missing) > 0 and not set(missing) <= set(
+        [
+            "encoder.embed_positions.weights",
+            "decoder.embed_positions.weights",
+        ]
+    ):
+        raise ValueError(
+            f"Only `encoder.embed_positions.weights` and `decoder.embed_positions.weights`  are allowed to be missing, but all the following weights are missing {missing}"
+        )
+
     if tie_embeds:
         model.lm_head = make_linear_from_emb(model.model.decoder.embed_tokens)
     else:
@@ -106,7 +116,7 @@ def convert_fairseq_s2t_checkpoint_to_tfms(checkpoint_path, pytorch_dump_folder_
 if __name__ == "__main__":
     parser = argparse.ArgumentParser()
     # Required parameters
-    parser.add_argument("fairseq_path", type=str, help="Path to the fairseq model (.pt) file.")
-    parser.add_argument("pytorch_dump_folder_path", default=None, type=str, help="Path to the output PyTorch model.")
+    parser.add_argument("--fairseq_path", type=str, help="Path to the fairseq model (.pt) file.")
+    parser.add_argument("--pytorch_dump_folder_path", default=None, type=str, help="Path to the output PyTorch model.")
     args = parser.parse_args()
     convert_fairseq_s2t_checkpoint_to_tfms(args.fairseq_path, args.pytorch_dump_folder_path)