[DCP] check return_lse for all layers in dcp (#27929)

Signed-off-by: Chen Zhang <zhangch99@outlook.com>

vllm/v1/worker/gpu_model_runner.py

@@ -4680,10 +4680,7 @@ class GPUModelRunner(LoRAModelRunnerMixin, KVConnectorModelRunnerMixin):
             kv_transfer_group.set_host_xfer_buffer_ops(copy_kv_blocks)
 
         if self.dcp_world_size > 1:
-            layer_names = self.attn_groups[0][0].layer_names
-            layers = get_layers_from_vllm_config(
-                self.vllm_config, AttentionLayerBase, layer_names
-            )
+            layers = get_layers_from_vllm_config(self.vllm_config, AttentionLayerBase)
             for layer in layers.values():
                 assert layer.impl.need_to_return_lse_for_decode, (
                     "DCP requires attention impls to return"