[ROCm][BugFix] Fix shared expert loading error when disable VLLM_ROCM_USE_AITER_FUSION_SHARED_EXPERTS (vllm-project#28633)

Signed-off-by: ganyi <ygan@amd.com>

Author: ganyi1996ppo

vllm/model_executor/models/deepseek_v2.py

@@ -287,7 +287,10 @@ def __init__(
         )
 
         self.is_rocm_aiter_moe_enabled = rocm_aiter_ops.is_fused_moe_enabled()
-        if config.n_shared_experts is None or self.is_rocm_aiter_moe_enabled:
+        self.is_fusion_moe_shared_experts_enabled = (
+            rocm_aiter_ops.is_fusion_moe_shared_experts_enabled()
+        )
+        if config.n_shared_experts is None or self.is_fusion_moe_shared_experts_enabled:
             self.shared_experts = None
         else:
             intermediate_size = config.moe_intermediate_size * config.n_shared_experts
@@ -327,7 +330,7 @@ def __init__(
             num_redundant_experts=self.n_redundant_experts,
             is_sequence_parallel=self.is_sequence_parallel,
             n_shared_experts=config.n_shared_experts
-            if rocm_aiter_ops.is_fusion_moe_shared_experts_enabled()
+            if self.is_fusion_moe_shared_experts_enabled
             else None,
         )