[https://nvbugs/5564465][fix] Overwrite only if default_max_tokens is legal (#8538)

Signed-off-by: Pengyun Lin <[email protected]>

Author: LinPoly

tensorrt_llm/executor/base_worker.py

@@ -432,7 +432,7 @@ def _deduce_max_tokens(request: GenerationRequest,
             # default_max_tokens is the biggest available value
             if max_tokens is None:
                 return default_max_tokens
-            elif max_tokens > default_max_tokens:
+            elif max_tokens > default_max_tokens and default_max_tokens > 0:
                 logger.warning(
                     f"User-specified `max_tokens` ({max_tokens}) is greater than deduced "
                     f"`default_max_tokens` ({default_max_tokens}), using default_max_tokens instead."