reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/sverdlin/linux/commit/f009754bffb9d03ce00b6336391ca82eb71138c8
        git remote add sverdlin https://github.com/sverdlin/linux
        git fetch --no-tags sverdlin snps-trng
        git checkout f009754bffb9d03ce00b6336391ca82eb71138c8
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash dtbs_check