reproduce (this is a W=1 build):
        git remote add drm-amdgpu https://gitlab.freedesktop.org/drm/amdgpu/kernel
        git fetch --no-tags drm-amdgpu drm-amdgpu-next
        git checkout 6f74688d7e2377e253671d36acd63a988186216b

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash