[Doc] fix DSV3.1 PD configs (#7187)

### What this PR does / why we need it?
Modify the `kv_port` and `engine_id` config of DeepSeek-V3.1/R1 in the
2P1D scenario

- vLLM version: v0.16.0
- vLLM main:
4034c3d32e

Signed-off-by: chenmenglong <chenmenglong1@huawei.com>

docs/source/tutorials/models/DeepSeek-V3.1.md

@@ -554,8 +554,8 @@ vllm serve /weights/DeepSeek-V3.1-w8a8-mtp-QuaRot \
   --kv-transfer-config \
   '{"kv_connector": "MooncakeConnectorV1",
   "kv_role": "kv_consumer",
-  "kv_port": "30300",
-  "engine_id": "3",
+  "kv_port": "30200",
+  "engine_id": "2",
   "kv_connector_extra_config": {
             "prefill": {
                     "dp_size": 2,