reproduce (this is a W=1 build):
        # https://github.com/jpirko/linux_mlxsw/commit/92dddc55f6a92701975cc749a90f9b33f0964f4d
        git remote add jpirko-mlxsw https://github.com/jpirko/linux_mlxsw
        git fetch --no-tags jpirko-mlxsw wip_dl_pfs_parent_v2
        git checkout 92dddc55f6a92701975cc749a90f9b33f0964f4d
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash CLIPPY=1 rustdoc