[spec decode] Fix MTP inference path for MiMo-7B model (#25136)

Signed-off-by: zixi-qi <qizixi@meta.com>
Co-authored-by: Cyrus Leung <tlleungac@connect.ust.hk>

examples/offline_inference/spec_decode.py

@@ -53,7 +53,6 @@ def parse_args():
         "--method",
         type=str,
         default="eagle",
-        choices=["ngram", "eagle", "eagle3", "mtp"],
     )
     parser.add_argument("--num-spec-tokens", type=int, default=2)
     parser.add_argument("--prompt-lookup-max", type=int, default=5)
@@ -118,6 +117,11 @@ def main():
             "prompt_lookup_max": args.prompt_lookup_max,
             "prompt_lookup_min": args.prompt_lookup_min,
         }
+    elif args.method.endswith("mtp"):
+        speculative_config = {
+            "method": args.method,
+            "num_speculative_tokens": args.num_spec_tokens,
+        }
     else:
         raise ValueError(f"unknown method: {args.method}")