ERROR: "ap_driver_register" undefined!

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   c0842fbc1b18c7a044e6ff3e8fa78bfa822c7d1a
commit: e93a1695d7fb551376b1c1220a267d032b6ad159 iommu: Enable compile testing for some of drivers
date:   5 months ago
config: s390-randconfig-m031-20200804 (attached as .config)
compiler: s390-linux-gcc (GCC) 9.3.0
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
        git checkout e93a1695d7fb551376b1c1220a267d032b6ad159
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=s390 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

>> ERROR: "ap_driver_register" [drivers/s390/crypto/vfio_ap.ko] undefined!
>> ERROR: "ap_driver_unregister" [drivers/s390/crypto/vfio_ap.ko] undefined!

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0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

Attachment: .config.gz
Description: application/gzip