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/mtd/linux.git/commit/?id=a11a51896572273d04a9f6011ad22738c52ba554
        git remote add mtd https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git
        git fetch --no-tags mtd nand/next
        git checkout a11a51896572273d04a9f6011ad22738c52ba554
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash drivers/spi/