[hardware] unify usage of is_tpu to current_platform.is_tpu() (#7102)

vllm/executor/ray_utils.py

@@ -2,8 +2,9 @@ from typing import List, Optional, Tuple, Union
 
 from vllm.config import ParallelConfig
 from vllm.logger import init_logger
+from vllm.platforms import current_platform
 from vllm.sequence import ExecuteModelRequest, IntermediateTensors
-from vllm.utils import get_ip, is_hip, is_tpu, is_xpu
+from vllm.utils import get_ip, is_hip, is_xpu
 from vllm.worker.worker_base import WorkerWrapperBase
 
 logger = init_logger(__name__)
@@ -111,7 +112,7 @@ def initialize_ray_cluster(
         # Placement group is already set.
         return
 
-    device_str = "GPU" if not is_tpu() else "TPU"
+    device_str = "GPU" if not current_platform.is_tpu() else "TPU"
     # Create placement group for worker processes
     current_placement_group = ray.util.get_current_placement_group()
     if current_placement_group: