[PATCH] x86_64: Don't reserve hotplug CPUs by default

Most users don't need it so no need to waste memory.
This means an user has to specify the appropiate number of
hotplug CPUs on the command line with additional_cpus=...
or fix their BIOS to follow the convention in
Documentation/x86-64/cpu-hotplug-spec

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>