[Bugfix][Benchmarks] Allow benchmark of deepspeed-mii backend to select a model (#17285)

Signed-off-by: Teruaki Ishizaki <teruaki.ishizaki@ntt.com>

benchmarks/backend_request_func.py

@@ -201,6 +201,7 @@ async def async_request_deepspeed_mii(
                                      timeout=AIOHTTP_TIMEOUT) as session:
 
         payload = {
+            "model": request_func_input.model,
             "prompt": request_func_input.prompt,
             "max_tokens": request_func_input.output_len,
             "temperature": 0.01,  # deepspeed-mii does not accept 0.0 temp.