ERROR: Input tree has errors, aborting (use -f to force output)

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git imx/dt
head:   aa4eab4468913b80fbed464abf1b94d64f0bb7cc
commit: 7f876822566dc2dd9fde51940941676651eacaef [15/22] ARM: dts: imx7s: Add SAI nodes
config: arm-multi_v7_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 5.4.0-6) 5.4.0 20160609

reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
git checkout 7f876822566dc2dd9fde51940941676651eacaef
# save the attached .config to linux build tree
make.cross ARCH=arm

Note: the shawnguo/imx/dt HEAD aa4eab4468913b80fbed464abf1b94d64f0bb7cc builds fine.
It only hurts bisectibility.

All errors (new ones prefixed by >>):

>> ERROR: Input tree has errors, aborting (use -f to force output)

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