Restore hygon qwen3_6 startup retries

Author: HermiaHuan

tests/platforms/hygon.yaml

@@ -54,7 +54,7 @@ device_overrides:
           disable_custom_all_reduce: false
           enable_log_requests: false
           enable_prefix_caching: false
-        startup_retries: null
+        startup_retries: 120
         sampling:
           temperature: 0.7