[Model][Spec Decode] Nemotron-H MTP and Mamba Speculative Decoding Support (#33726)

Signed-off-by: Shahar Mor <smor@nvidia.com>
Signed-off-by: Benjamin Chislett <bchislett@nvidia.com>
Signed-off-by: Lucas Wilkinson <lwilkins@redhat.com>
Co-authored-by: Shahar Mor <smor@nvidia.com>
Co-authored-by: Roi Koren <roik@nvidia.com>
Co-authored-by: Lucas Wilkinson <lwilkins@redhat.com>

vllm/config/vllm.py

@@ -395,6 +395,15 @@ class VllmConfig:
         ]
         return hash_str
 
+    @property
+    def num_speculative_tokens(self) -> int:
+        if (
+            self.speculative_config is not None
+            and self.speculative_config.num_speculative_tokens is not None
+        ):
+            return self.speculative_config.num_speculative_tokens
+        return 0
+
     @property
     def needs_dp_coordinator(self) -> bool:
         """