[Misc] Add SPDX-License-Identifier headers to python source files (#12628)

- **Add SPDX license headers to python source files**
- **Check for SPDX headers using pre-commit**

commit 9d7ef44c3cfb72ca4c32e1c677d99259d10d4745
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:18:24 2025 -0500

    Add SPDX license headers to python source files
    
This commit adds SPDX license headers to python source files as
recommended to
the project by the Linux Foundation. These headers provide a concise way
that is
both human and machine readable for communicating license information
for each
source file. It helps avoid any ambiguity about the license of the code
and can
    also be easily used by tools to help manage license compliance.
    
The Linux Foundation runs license scans against the codebase to help
ensure
    we are in compliance with the licenses of the code we use, including
dependencies. Having these headers in place helps that tool do its job.
    
    More information can be found on the SPDX site:
    
    - https://spdx.dev/learn/handling-license-info/

Signed-off-by: Russell Bryant <rbryant@redhat.com>

commit 5a1cf1cb3b80759131c73f6a9dddebccac039dea
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:36:32 2025 -0500

    Check for SPDX headers using pre-commit
Signed-off-by: Russell Bryant <rbryant@redhat.com>

---------
Signed-off-by: Russell Bryant <rbryant@redhat.com>

vllm/model_executor/layers/quantization/gptq_marlin.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Any, Callable, Dict, List, Optional, Set, Union
 
 import torch

vllm/model_executor/layers/quantization/gptq_marlin_24.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Any, Dict, List, Optional
 
 import torch

vllm/model_executor/layers/quantization/hqq_marlin.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Any, Dict, List, Optional
 
 import torch

vllm/model_executor/layers/quantization/ipex_quant.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Any, Dict, List, Optional
 
 import torch

vllm/model_executor/layers/quantization/kernels/mixed_precision/MPLinearKernel.py

+# SPDX-License-Identifier: Apache-2.0
+
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from typing import Callable, Optional, Tuple

vllm/model_executor/layers/quantization/kernels/mixed_precision/__init__.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import List, Optional, Type
 
 import vllm.envs as envs

vllm/model_executor/layers/quantization/kernels/mixed_precision/exllama.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Optional, Tuple
 
 import torch

vllm/model_executor/layers/quantization/kernels/mixed_precision/machete.py

+# SPDX-License-Identifier: Apache-2.0
+
 from functools import partial
 from typing import Optional, Tuple
 

vllm/model_executor/layers/quantization/kernels/mixed_precision/marlin.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Optional, Tuple
 
 import torch

vllm/model_executor/layers/quantization/kernels/scaled_mm/ScaledMMLinearKernel.py

+# SPDX-License-Identifier: Apache-2.0
+
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from typing import Optional, Tuple

vllm/model_executor/layers/quantization/kernels/scaled_mm/__init__.py

+# SPDX-License-Identifier: Apache-2.0
+
 import os
 from typing import Dict, List, Optional, Type
 

vllm/model_executor/layers/quantization/kernels/scaled_mm/cutlass.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Optional, Tuple
 
 import torch

vllm/model_executor/layers/quantization/kernels/scaled_mm/triton.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Optional, Tuple
 
 import torch

vllm/model_executor/layers/quantization/kernels/scaled_mm/xla.py

+# SPDX-License-Identifier: Apache-2.0
+
 import warnings
 from typing import Optional, Tuple
 

vllm/model_executor/layers/quantization/kv_cache.py

+# SPDX-License-Identifier: Apache-2.0
+
 import torch
 
 from vllm.logger import init_logger

vllm/model_executor/layers/quantization/marlin.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Any, Dict, List, Optional
 
 import torch

vllm/model_executor/layers/quantization/modelopt.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Any, Dict, List, Optional
 
 import torch

vllm/model_executor/layers/quantization/moe_wna16.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Any, Callable, Dict, List, Optional
 
 import torch

vllm/model_executor/layers/quantization/neuron_quant.py

+# SPDX-License-Identifier: Apache-2.0
+
 import os
 from importlib.util import find_spec
 from typing import Any, Dict, List, Optional

vllm/model_executor/layers/quantization/qqq.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Any, Dict, List, Optional
 
 import torch