powerpc: ERROR: modpost: "efx_tc_netevent_event" [drivers/net/ethernet/sfc/sfc.ko] undefined!

Following build regressions noticed on Linux next-20230615.

Reported-by: Linux Kernel Functional Testing lkft@linaro.org

Regressions found on powerpc:

- build/gcc-8-ppc6xx_defconfig - build/gcc-12-ppc6xx_defconfig

buid log: ==== ERROR: modpost: "efx_tc_netevent_event" [drivers/net/ethernet/sfc/sfc.ko] undefined! ERROR: modpost: "efx_tc_netdev_event" [drivers/net/ethernet/sfc/sfc.ko] undefined! make[2]: *** [/builds/linux/scripts/Makefile.modpost:137: Module.symvers] Error 1

Links: - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230615/tes... - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230615/tes...

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