[V0 Deprecation] Remove async_output_proc, preemption mode, delay factor (#25334)

Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>

vllm/platforms/rocm.py

@@ -310,16 +310,6 @@ class RocmPlatform(Platform):
         device_props = torch.cuda.get_device_properties(device_id)
         return device_props.total_memory
 
-    @classmethod
-    def is_async_output_supported(cls, enforce_eager: Optional[bool]) -> bool:
-        if enforce_eager and not envs.VLLM_USE_V1:
-            logger.warning(
-                "To see benefits of async output processing, enable CUDA "
-                "graph. Since, enforce-eager is enabled, async output "
-                "processor cannot be used")
-            return False
-        return True
-
     @classmethod
     def check_and_update_config(cls, vllm_config: "VllmConfig") -> None:
         from vllm.config.compilation import CUDAGraphMode