[refactor] Add prefix support to embed_tokens in DeepSeek MTP (#30788)

Signed-off-by: zzhx1 <zzh_201018@outlook.com>

vllm/model_executor/models/deepseek_mtp.py

@@ -141,6 +141,7 @@ class DeepSeekMultiTokenPredictor(nn.Module):
         self.embed_tokens = VocabParallelEmbedding(
             config.vocab_size,
             config.hidden_size,
+            prefix=maybe_prefix(prefix, "embed_tokens"),
         )
         self.logits_processor = LogitsProcessor(config.vocab_size)