Originally, before this set of patches moving stuff out from kernel/ksyms.c,
set_cpus_schedule was EXPORT_SYMBOL_GPL, my mistake, bring it back.

Also follow Andrew Morton's suggestions of moving the EXPORT_SYMBOL{_GPL) even
closer to the place where the symbol exported is defined, i.e. just after the
symbol definition, this makes mistakes more difficult to happen, as when the
symbol definition is #ifdefed the EXPORT_SYMBOL{_GPL} is in the same block.