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/jmondi/linux.git/commit/?id=e3a052ed7a909d2f9d7f52992b1ee842745c9347
        git remote add jmondi https://git.kernel.org/pub/scm/linux/kernel/git/jmondi/linux.git
        git fetch --no-tags jmondi imx8mp/iob-gitlab/v6.9/extensible-format-v6+bls-v2+fix
        git checkout e3a052ed7a909d2f9d7f52992b1ee842745c9347
        # 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