reproduce (this is a W=1 build):
        # https://github.com/intel/linux-intel-lts/commit/edde945257e28104cf865d7d2b9b239f87d815d4
        git remote add intel-lts https://github.com/intel/linux-intel-lts.git
        git fetch --no-tags intel-lts pr/57
        git checkout edde945257e28104cf865d7d2b9b239f87d815d4
        # 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/iio/dac/