[Dist][EP] Remove ETP/EP maintained in vllm-ascend (#1681)

### What this PR does / why we need it?
Remove ETP/EP maintained in branch main. We drop this as there is no
relevant scenarios to use ETP now, and we may subsequently advocate
implementing expert tensor parallelism in vLLM to support scenarios
where the expert is needed to be sliced

This is a part of #1422 backport.

Fixes https://github.com/vllm-project/vllm-ascend/issues/1396
https://github.com/vllm-project/vllm-ascend/issues/1154

### Does this PR introduce _any_ user-facing change?
We'll not maintain etp/ep in vllm-ascend anymore, and use the tp/ep in
vllm instead.

### How was this patch tested?
CI passed with new added and existing test.


- vLLM version: v0.9.2
- vLLM main:
fe8a2c544a

Signed-off-by: MengqingCao <cmq0113@163.com>

docs/source/user_guide/configuration/additional_config.md

@@ -28,7 +28,6 @@ The following table lists the additional configuration options available in vLLM
 |-------------------------------| ---- |------|-----------------------------------------------------------------------------------------------|
 | `torchair_graph_config`       | dict | `{}` | The config options for torchair graph mode                                                    |
 | `ascend_scheduler_config`     | dict | `{}` | The config options for ascend scheduler                                                       |
-| `expert_tensor_parallel_size` | str  | `0`  | Expert tensor parallel size the model to use.                                                 |
 | `refresh`                     | bool | `false` | Whether to refresh global ascend config content. This value is usually used by rlhf or ut/e2e test case.     |
 | `expert_map_path`             | str  | `None` | When using expert load balancing for the MOE model, an expert map path needs to be passed in. |
 | `chunked_prefill_for_mla`     | bool | `False` | Whether to enable the fused operator-like chunked_prefill. |
@@ -75,7 +74,6 @@ An example of additional configuration is as follows:
         "enabled": True,
         "enable_chunked_prefill": True,
     },
-    "expert_tensor_parallel_size": 1,
     "refresh": False,
 }
 ```