spec : remove tokens assert from dsv4 graph_mtp (#30444)

cont of #29622, where we forgot to remove token assert

src/models/deepseek4.cpp

@@ -1366,7 +1366,6 @@ llama_model_deepseek4::graph_mtp::graph_mtp(const llama_model & model, const llm
             cparams.nextn_layer_offset < (int) hparams.n_layer_nextn &&
             "nextn_layer_offset out of range [0, n_layer_nextn)");
     ASSERT_EMBD_OR_TOKEN(ubatch);
-    GGML_ASSERT(ubatch.token && "DEEPSEEK4 MTP requires token input");
 
     const int64_t hc = hparams.dsv4_hc_mult;
     GGML_ASSERT(hparams.n_embd_out() == (uint32_t) (n_embd*hc) && "DEEPSEEK4 MTP hidden width mismatch");