[EPLB][Bugfix] Dispatch Allgather use log2phy if enable eplb (#5933)

### What this PR does / why we need it?
1. Move the logic of expert mapping forward to prevent shotgun changes
2. Disable the update of expert map.

### How was this patch tested?
a2
| dataset | version | metric | mode | vllm-api-general-chat |
|----- | ----- | ----- | ----- | -----|
| GPQA_diamond | 53064e | accuracy | gen | 73.23 |

a3
| dataset | version | metric | mode | vllm-api-general-chat |
|----- | ----- | ----- | ----- | -----|
| aime2024 | 604a78 | accuracy | gen | 83.33 |


- vLLM version: v0.13.0
- vLLM main:
11b6af5280

Signed-off-by: shenchuxiaofugui <1311027364@qq.com>

vllm_ascend/ops/fused_moe/fused_moe.py

@@ -150,7 +150,6 @@ class AscendUnquantizedFusedMoEMethod(UnquantizedFusedMoEMethod):
             w2=layer.w2_weight,
             topk_weights=topk_weights,
             topk_ids=topk_ids,
-            global_num_experts=global_num_experts,
             expert_map=expert_map,
             apply_router_weight_on_input=apply_router_weight_on_input,
             dynamic_eplb=self.dynamic_eplb,