Add pt_load_map_location to allow loading to cuda (#16869)

Signed-off-by: Jerry Zhang <jerryzh168@gmail.com>

tests/test_config.py

@@ -5,7 +5,8 @@ from typing import Literal, Union
 
 import pytest
 
-from vllm.config import ModelConfig, PoolerConfig, config, get_field
+from vllm.config import (LoadConfig, ModelConfig, PoolerConfig, VllmConfig,
+                         config, get_field)
 from vllm.model_executor.layers.pooler import PoolingType
 from vllm.platforms import current_platform
 
@@ -410,3 +411,16 @@ def test_generation_config_loading():
         override_generation_config=override_generation_config)
 
     assert model_config.get_diff_sampling_param() == override_generation_config
+
+
+@pytest.mark.parametrize("pt_load_map_location", [
+    "cuda",
+    {
+        "": "cuda"
+    },
+])
+def test_load_config_pt_load_map_location(pt_load_map_location):
+    load_config = LoadConfig(pt_load_map_location=pt_load_map_location)
+    config = VllmConfig(load_config=load_config)
+
+    assert config.load_config.pt_load_map_location == pt_load_map_location