add attn_groups judge

Author: wucong25

vllm_ascend/worker/model_runner_v1.py

@@ -2697,7 +2697,8 @@ def initialize_kv_cache(self, kv_cache_config: KVCacheConfig) -> None:
         self.kv_cache_config = kv_cache_config
         self.may_add_encoder_only_layers_to_kv_cache_config()
         # NOTE(cmq): initialize_attn_backend must before using self.attn_groups
-        self.initialize_attn_backend(kv_cache_config)
+        if not self.attn_groups:
+            self.initialize_attn_backend(kv_cache_config)
         self.use_hybrid_blocks = (len(self.attn_groups) > 1)
         # NOTE: Currently, we determine whether we need `num_accepted_tokens` through `MambaSpec`.
         self.need_accepted_tokens = any([