reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/spacemit-com/linux/commit/9aebdfc21f755e0d2766683aa251435fb656ea47
        git remote add spacemit https://github.com/spacemit-com/linux
        git fetch --no-tags spacemit k1/for-next
        git checkout 9aebdfc21f755e0d2766683aa251435fb656ea47
        # 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