[RL] [V1] Remove unused device argument from reset_kv_cache (#28766)

Signed-off-by: Zhuohan Li <zhuohan123@gmail.com>

vllm/entrypoints/llm.py

@@ -32,7 +32,6 @@ from vllm.config.model import (
     TokenizerMode,
 )
 from vllm.engine.arg_utils import EngineArgs
-from vllm.engine.protocol import Device
 from vllm.entrypoints.chat_utils import (
     ChatCompletionMessageParam,
     ChatTemplateContentFormatOption,
@@ -1499,8 +1498,8 @@ class LLM:
     def stop_profile(self) -> None:
         self.llm_engine.stop_profile()
 
-    def reset_prefix_cache(self, device: Device | None = None) -> None:
-        self.llm_engine.reset_prefix_cache(device)
+    def reset_prefix_cache(self) -> None:
+        self.llm_engine.reset_prefix_cache()
 
     def sleep(self, level: int = 1):
         """