reproduce (this is a W=1 build):
        # https://github.com/frank-w/BPI-R2-4.14/commit/94b835dbea00af284bc4e77880675c828f3d7f80
        git remote add frank-w-bpi-r2-4.14 https://github.com/frank-w/BPI-R2-4.14
        git fetch --no-tags frank-w-bpi-r2-4.14 6.12-rsslro
        git checkout 94b835dbea00af284bc4e77880675c828f3d7f80
        # 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 drivers/net/phy/ tools/testing/selftests/arm64/tags/