[BugFix] Fix data parallel (#940)

### What this PR does / why we need it?
With this PR, we can migrate to the native `data_parallel.py` in vllm
examples and remove the version in vllm-ascend.

At present, `ASCEND_RT_VISIBLE_DEVICES` introduces considerable
difficulties; therefore, we must employ a temporary workaround and
manually specify the device.

Signed-off-by: Yizhou Liu <liu_yizhou@outlook.com>

vllm_ascend/worker/worker_v1.py

@@ -74,6 +74,13 @@ class NPUWorker(WorkerBase):
                          rank=rank,
                          distributed_init_method=distributed_init_method,
                          is_driver_worker=is_driver_worker)
+
+        # NOTE(Yizhou): Since we do not set ASCEND_RT_VISIBLE_DEVICES in
+        # vllm_ascend, we need to set the device id manually.
+        local_dp_rank = self.vllm_config.parallel_config.data_parallel_rank_local
+        world_size = self.vllm_config.parallel_config.world_size
+        self.local_rank_across_dp = local_dp_rank * world_size + self.local_rank
+
         # Try to import mindie_turbo to accelerate vLLM inference.
         try_register_lib(
             "mindie_turbo",
@@ -112,7 +119,7 @@ class NPUWorker(WorkerBase):
 
     def init_device(self):
         if self.device_config.device.type == "npu":
-            self.device = torch.device(f"npu:{self.local_rank}")
+            self.device = torch.device(f"npu:{self.local_rank_across_dp}")
             NPUPlatform.set_device(self.device)
             NPUPlatform.empty_cache()
             self.init_npu_memory = NPUPlatform.mem_get_info()[0]