reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/krzk/linux/commit/d62bcc0529c132bdd0826953ebd81888d90c9d7f
        git remote add krzk-github https://github.com/krzk/linux
        git fetch --no-tags krzk-github b4/dt-bindings-mfd-syscon-split
        git checkout d62bcc0529c132bdd0826953ebd81888d90c9d7f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=mips olddefconfig
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash dtbs_check