reproduce (this is a W=1 build):
        # https://github.com/krzk/linux/commit/75388fe67f2ecd0bfcf603417b8fdede84d3d6b3
        git remote add krzk-github https://github.com/krzk/linux
        git fetch --no-tags krzk-github b4/of-match-machine-data
        git checkout 75388fe67f2ecd0bfcf603417b8fdede84d3d6b3

        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc64-linux-gnu
        # clang-22 might not be officially released. Try a lower version if installation fails.
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash drivers/cpufreq/