The build is failing with CONFIG_NUMA=n and some compiler versions:
arch/powerpc/platforms/pseries/hotplug-cpu.o: In function `dlpar_online_cpu':
hotplug-cpu.c:(.text+0x12c): undefined reference to `timed_topology_update'
arch/powerpc/platforms/pseries/hotplug-cpu.o: In function `dlpar_cpu_remove':
hotplug-cpu.c:(.text+0x400): undefined reference to `timed_topology_update'
Fix it by moving the empty version of timed_topology_update() into the
existing #ifdef block, which has the right guard of SPLPAR && NUMA.
Fixes: cee5405da4 ("powerpc/hotplug: Improve responsiveness of hotplug change")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
6c0a8f6b5a