fix mtp config and padding

[luccafong]

fix mtp config with latest code and HF config

ran gsm8k num_fewshot=20 with TP=8 in eager mode:

VLLM_USE_DEEP_GEMM=0  VLLM_MLA_SPARSE_ENABLED=1 vllm serve "deepseek-ai/DeepSeek-V3.2-Exp" --max_model_len=20000 --gpu_memory_utilization=0.9 --tensor_parallel_size 8 --max_num_seqs=256 --speculative_config '{"num_speculative_tokens":1}' --enforce-eager

lm_eval --model local-completio
ns --tasks gsm8k     --model_args model=deepseek-ai/DeepSeek-V3
.2-Exp,base_url=http://127.0.0.1:8000/v1/completions,num_concur
rent=32,max_retries=3,tokenized_requests=False --batch_size 32 
--num_fewshot 20

|-----|------:|----------------|-----:|-----------|---|-----:|---|-----:|
|gsm8k|      3|flexible-extract|    20|exact_match|↑  |0.9538|±  |0.0058|
|     |       |strict-match    |    20|exact_match|↑  |0.9538|±  |0.0058|

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[heheda12345]

Thanks for the fix!