[Misc]Replace `cuda` hard code with `current_platform` in Ray (#14668)

Signed-off-by: noemotiovon <757486878@qq.com>

vllm/executor/ray_utils.py

@@ -87,9 +87,8 @@ try:
             # TODO(swang): This is needed right now because Ray Compiled Graph
             # executes on a background thread, so we need to reset torch's
             # current device.
-            import torch
             if not self.compiled_dag_cuda_device_set:
-                torch.cuda.set_device(self.worker.device)
+                current_platform.set_device(self.worker.device)
                 self.compiled_dag_cuda_device_set = True
 
             output = self.worker._execute_model_spmd(execute_model_req,
@@ -113,8 +112,7 @@ try:
                     # Not needed
                     pass
                 else:
-                    import torch
-                    torch.cuda.set_device(self.worker.device)
+                    current_platform.set_device(self.worker.device)
 
                 self.compiled_dag_cuda_device_set = True