Fix DeepEP error in some environments (#7154)

python/sglang/srt/layers/moe/ep_moe/token_dispatcher.py

@@ -107,6 +107,8 @@ class DeepEPBuffer:
             num_rdma_bytes,
             low_latency_mode=deepep_mode.enable_low_latency(),
             num_qps_per_rank=num_qps_per_rank,
+            # TODO can be false when unneeded
+            allow_mnnvl=True,
         )
         return cls._buffer