[bugfix] Repair the problem of moe model accuracy caused by version upgrade. (#4562)

Repair the problem of moe model accuracy caused by version upgrade.

Reason:
The new version adds the "reduce_output" operation after "forward_impl".

Then we have fully taken over the implementation of the FusedMoe module.


- vLLM version: v0.11.2
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.2

---------

Signed-off-by: weijinqian_v1 <weijinqian@huawei.com>
Co-authored-by: weijinqian_v1 <weijinqian@huawei.com>

vllm_ascend/ops/fused_moe/fused_moe.py

@@ -18,6 +18,7 @@ import os.path
 from typing import Any, Callable, Optional
 
 import torch
+import torch.nn.functional as F
 import torch_npu
 from vllm.config import get_current_vllm_config
 from vllm.distributed import (get_dp_group, get_ep_group, get_tp_group,
@@ -292,6 +293,32 @@ class AscendFusedMoE(FusedMoE):
         return torch.ops.vllm.maybe_all_reduce_tensor_model_parallel(
             final_hidden_states)
 
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        router_logits: torch.Tensor,
+    ) -> torch.Tensor | tuple[torch.Tensor, torch.Tensor]:
+        og_hidden_states = hidden_states.shape[-1]
+        if self.hidden_size != og_hidden_states:
+            hidden_states = F.pad(
+                hidden_states,
+                (0, self.hidden_size - og_hidden_states),
+                mode="constant",
+                value=0.0,
+            )
+        if self.shared_experts is None:
+            fused_output = torch.ops.vllm.moe_forward(hidden_states,
+                                                      router_logits,
+                                                      self.layer_name)
+            return fused_output[..., :og_hidden_states]
+        else:
+            shared_output, fused_output = torch.ops.vllm.moe_forward_shared(
+                hidden_states, router_logits, self.layer_name)
+            return (
+                shared_output[..., :og_hidden_states],
+                fused_output[..., :og_hidden_states],
+            )
+
     def forward_impl(self, hidden_states: torch.Tensor,
                      router_logits: torch.Tensor):
         assert self.quant_method is not None