ERROR: "rational_best_approximation" [drivers/tty/serial/8250/8250_mid.ko] undefined!

[kbuild test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   8005c49d9aea74d382f474ce11afbbc7d7130bec
commit: d9eda9bab237259b06690652b145d19e0ce37a77 serial: 8250_pci: Intel MID UART support to its own driver
date:   4 weeks ago
config: x86_64-randconfig-s5-11170458 (attached as .config)
reproduce:
        git checkout d9eda9bab237259b06690652b145d19e0ce37a77
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

>> ERROR: "rational_best_approximation" [drivers/tty/serial/8250/8250_mid.ko] undefined!

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0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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