reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install powerpc64 cross compiling tool for clang build
        # apt-get install binutils-powerpc64-linux-gnu
        # https://github.com/lunn/linux/commit/c4ae49b10529d66ed1aa9bf7c6e10ef95dfe7f75
        git remote add lunn https://github.com/lunn/linux.git
        git fetch --no-tags lunn v6.8.0-net-next-mv88e6xxx-leds-v4
        git checkout c4ae49b10529d66ed1aa9bf7c6e10ef95dfe7f75
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash drivers/net/ethernet/intel/igc/