[arm:cex7 84/92] ERROR: modpost: ".of_mdio_find_device" undefined!

tree:   git://git.armlinux.org.uk/~rmk/linux-arm.git cex7
head:   1cf4cc764b1d6b6fbb23bed77dd3ea934ab91506
commit: fd8493d67f38148862c78c3d92266d6451791426 [84/92] dpaa2-mac: add 1000BASE-X/SGMII PCS support
config: powerpc-allmodconfig (attached as .config)
compiler: powerpc64-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 fd8493d67f38148862c78c3d92266d6451791426
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc 

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

All errors (new ones prefixed by >>, old ones prefixed by <<):

quoted

ERROR: modpost: ".of_mdio_find_device" [drivers/net/ethernet/freescale/dpaa2/fsl-dpaa2-eth.ko] undefined!

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