reproduce (this is a W=1 build):
        # https://github.com/avpatel/linux/commit/7a9f321e07211295d163e3e5387abc7f2889e791
        git remote add avpatel https://github.com/avpatel/linux.git
        git fetch --no-tags avpatel riscv_raid6_rvv_v5
        git checkout 7a9f321e07211295d163e3e5387abc7f2889e791
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um olddefconfig
        make W=1 O=build_dir ARCH=um SHELL=/bin/bash drivers/clk/