Revert "Re-land "Add INT8 SDPA path for CPU" (#2093)"

This reverts commit 137b079.

Author: atalman

setup.py

@@ -55,10 +55,6 @@ def read_version(file_path="version.txt"):
     and platform.system() == "Darwin"
 )
 
-use_cpp_avx512 = os.getenv("USE_AVX512", "1") == "1" and platform.system() == "Linux"
-
-from torchao.utils import TORCH_VERSION_AT_LEAST_2_7
-
 version_prefix = read_version()
 # Version is version.dev year month date if using nightlies and version if not
 version = (
@@ -288,17 +284,6 @@ def get_extensions():
             ["-O3" if not debug_mode else "-O0", "-fdiagnostics-color=always"]
         )
 
-        if use_cpp_avx512 and TORCH_VERSION_AT_LEAST_2_7:
-            if torch._C._cpu._is_avx512_supported():
-                extra_compile_args["cxx"].extend(
-                    [
-                        "-DCPU_CAPABILITY_AVX512",
-                        "-march=native",
-                        "-mfma",
-                        "-fopenmp",
-                    ]
-                )
-
         if debug_mode:
             extra_compile_args["cxx"].append("-g")
             if "nvcc" in extra_compile_args:
@@ -320,12 +305,6 @@ def get_extensions():
 
     # Collect C++ source files
     sources = list(glob.glob(os.path.join(extensions_dir, "**/*.cpp"), recursive=True))
-    if IS_WINDOWS:
-        # Remove csrc/cpu/*.cpp on Windows due to the link issue: unresolved external symbol PyInit__C
-        excluded_sources = list(
-            glob.glob(os.path.join(extensions_dir, "cpu/*.cpp"), recursive=True)
-        )
-        sources = [s for s in sources if s not in excluded_sources]
 
     extensions_cuda_dir = os.path.join(extensions_dir, "cuda")
     cuda_sources = list(