reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/sverdlin/linux/commit/21e232768cb64142db24034d3dceffbc48c2447e
        git remote add sverdlin https://github.com/sverdlin/linux
        git fetch --no-tags sverdlin snps-trng
        git checkout 21e232768cb64142db24034d3dceffbc48c2447e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash dtbs_check