tinyconfig: kernel/time/timekeeping.c:286:1: error: no return statement in function returning non-void [-Werror=return-type]

[Naresh Kamboju]

The powerpc,s390, superSh and sparc tinyconfig builds failed due to
following build
warnings / errors on the Linux next-20240410 with gcc-13 and gcc-11.

List build failures:
---
* s390, build
  - gcc-13-tinyconfig - failed
  - gcc-8-tinyconfig - failed

* sh, build
  - gcc-11-tinyconfig - failed

* sparc, build
  - gcc-11-tinyconfig - failed

* mips, build
  - gcc-12-tinyconfig - failed
  - gcc-8-tinyconfig - failed

* powerpc, build
  - gcc-13-tinyconfig - failed
  - gcc-8-tinyconfig - failed

Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>

Build log:
--------
kernel/time/timekeeping.c: In function 'timekeeping_debug_get_ns':
kernel/time/timekeeping.c:286:1: error: no return statement in
function returning non-void [-Werror=return-type]
  286 | }
      | ^
cc1: some warnings being treated as errors

steps to reproduce:
---
# tuxmake --runtime podman --target-arch powerpc --toolchain gcc-13
--kconfig tinyconfig

Links:
 - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240410/testrun/23380322/suite/build/test/gcc-13-tinyconfig/details/
 - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240410/testrun/23380301/suite/build/test/gcc-11-tinyconfig/history/
 - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240410/testrun/23380301/suite/build/tests/

--
Linaro LKFT
https://lkft.linaro.org