Fix test

Author: mdboom

cuda_core/tests/system/test_system_device.py

@@ -733,14 +733,14 @@ def test_pstates():
 
 def test_nvlink():
     for device in system.Device.get_all_devices():
-        max_links = system.NvlinkInfo.max_links
+        max_links = _device.NvlinkInfo.max_links
         assert isinstance(max_links, int)
         assert max_links > 0
 
         for link in range(max_links):
             with unsupported_before(device, None):
                 nvlink_info = device.nvlink(link)
-            assert isinstance(nvlink_info, system.NvlinkInfo)
+            assert isinstance(nvlink_info, _device.NvlinkInfo)
 
             with unsupported_before(device, None):
                 version = nvlink_info.version