reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel.git/commit/?id=18b4e571dc82ac91ae9a39e169c8de285845b80c
        git remote add geert-renesas-devel https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel.git
        git fetch --no-tags geert-renesas-devel master
        git checkout 18b4e571dc82ac91ae9a39e169c8de285845b80c
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm64 olddefconfig
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash dtbs_check