[Refactor] Reducing code duplication across FP8 CUDA quantization kernels (#4163)

sgl-kernel/benchmark/bench_per_token_group_quant_fp8.py

@@ -1,13 +1,12 @@
 import itertools
-import math
-from typing import Any, Dict, List, Optional, Tuple
+from typing import Tuple
 
 import torch
 import triton
 import triton.language as tl
 from sgl_kernel import sgl_per_token_group_quant_fp8
 
-from sglang.srt.utils import get_device_core_count, get_device_name, is_hip
+from sglang.srt.utils import is_hip
 
 is_hip_ = is_hip()
 fp8_type_ = torch.float8_e4m3fnuz if is_hip_ else torch.float8_e4m3fn