[BugFix]fix Qwen3 MoE call gate twice (#40664)

Signed-off-by: Kunshang Ji <kunshang.ji@intel.com>

vllm/model_executor/models/qwen3_moe.py

@@ -231,7 +231,15 @@ class Qwen3MoeSparseMoeBlock(nn.Module):
         if self.is_sequence_parallel:
             hidden_states = sequence_parallel_chunk(hidden_states)
 
-        # router_logits: (num_tokens, n_experts)
+        if self.experts.is_internal_router:
+            # In this case, the gate/router runs inside the FusedMoE class
+            final_hidden_states = self.experts(
+                hidden_states=hidden_states, router_logits=hidden_states
+            )
+        else:
+            # Actually this will be dead code, since we always pass gate into
+            # FusedMoE in the current implementation. But we keep this code
+            # here for clarity and future flexibility.
             router_logits, _ = self.gate(hidden_states)
             final_hidden_states = self.experts(
                 hidden_states=hidden_states, router_logits=router_logits