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/at91/linux.git/commit/?id=371a47c9a58a13e339fce2a3118c9ee6a8422258
        git remote add at91 https://git.kernel.org/pub/scm/linux/kernel/git/at91/linux.git
        git fetch --no-tags at91 at91-dt
        git checkout 371a47c9a58a13e339fce2a3118c9ee6a8422258
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm olddefconfig
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash dtbs_check