These variables are only used when CONFIG_HOTPLUG_CPU is enabled, they are
ifdef'ed everywhere else.  So don't define them when CONFIG_HOTPLUG_CPU is
not enabled.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>