[morse:virtual_cpu_hotplug/rfc/v1 20/32] drivers/base/cpu.c:504:9: error: implicit declaration of function 'unregister_cpu'; did you mean 'register_cpu'?

[kernel test robot <lkp@intel.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git virtual_cpu_hotplug/rfc/v1
head:   81295db7555df74bd02dab0b7e87b512d3a3de34
commit: 9048fbcbea6dd1dfa42a3b9409695ff9199a417d [20/32] drivers: base: Implement weak arch_unregister_cpu()
config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20230204/202302042001.avSllcZk-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/commit/?id=9048fbcbea6dd1dfa42a3b9409695ff9199a417d
        git remote add morse https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git
        git fetch --no-tags morse virtual_cpu_hotplug/rfc/v1
        git checkout 9048fbcbea6dd1dfa42a3b9409695ff9199a417d
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash drivers/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/base/cpu.c: In function 'arch_unregister_cpu':
>> drivers/base/cpu.c:504:9: error: implicit declaration of function 'unregister_cpu'; did you mean 'register_cpu'? [-Werror=implicit-function-declaration]
     504 |         unregister_cpu(&per_cpu(cpu_devices, num));
         |         ^~~~~~~~~~~~~~
         |         register_cpu
   cc1: some warnings being treated as errors


vim +504 drivers/base/cpu.c

   501	
   502	void __weak arch_unregister_cpu(int num)
   503	{
 > 504		unregister_cpu(&per_cpu(cpu_devices, num));
   505	}
   506	#endif
   507	

-- 
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https://github.com/intel/lkp-tests