reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        git checkout fc033cf25e612e840e545f8d5ad2edd6ba613ed5
        b4 shazam https://lore.kernel.org/r/20250102-mpc83xx-v1-16-86f78ba2a7af@posteo.net
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash dtbs_check