ACPI: Allow hot-add of ejected processor

acpi_eject_store() didn't trim processors, causing subsequent
hot-add to fail.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>