undefined reference to `led_classdev_unregister'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62
commit: 7d9ee2e8ff1541c60dcb5cfdf41def9659204c3e net: dsa: hellcreek: Add PTP status LEDs
date:   9 weeks ago
config: microblaze-randconfig-r016-20210106 (attached as .config)
compiler: microblaze-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
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7d9ee2e8ff1541c60dcb5cfdf41def9659204c3e
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 7d9ee2e8ff1541c60dcb5cfdf41def9659204c3e
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=microblaze 

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

All errors (new ones prefixed by >>):

   microblaze-linux-ld: drivers/net/dsa/hirschmann/hellcreek_ptp.o: in function `hellcreek_ptp_setup':
>> (.text+0xf80): undefined reference to `led_classdev_register_ext'
>> microblaze-linux-ld: (.text+0xf94): undefined reference to `led_classdev_register_ext'
   microblaze-linux-ld: drivers/net/dsa/hirschmann/hellcreek_ptp.o: in function `hellcreek_ptp_free':
>> (.text+0x1018): undefined reference to `led_classdev_unregister'
>> microblaze-linux-ld: (.text+0x1024): undefined reference to `led_classdev_unregister'

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

Attachment: .config.gz
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