reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/jsarha/linux/commit/0cd2491bb127c67f683085510db07dd59f66d32f
        git remote add jsarha https://github.com/jsarha/linux
        git fetch --no-tags jsarha topic/cros-sof-v4.14-rebase
        git checkout 0cd2491bb127c67f683085510db07dd59f66d32f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-7.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-7.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash ./ drivers/gpu/ mm/