ACPI based physical CPU hotplug support for x86_64

Hi Andi/Andrew

Here are a set of patches to implement physical cpu hotplug for x86_64 arch.

Physical cpu hotplug support is already available for ia64, these set of
patches extend support for x86_64 as well.

Patches are split as follows. Please help the first 3 patches stage
in -mm before considering for mainline inclusion. The last 2 patches are
purely for testing. 

1. remove-processor-entries-on-eject - Minor bugfix to current base code.
2. remove-unused-lapic-entry		 - Remove unnecessary lapic definition
3. x86_64-physical-cpu-hotplug.patch - Physical cpu hotplug support for x86_64

The following two patches are not for mainline inclusion. They exist so 
we could test the code paths to test physical hotplug without need for a 
platform that is capable of hotplug. 

Procedure to do this is included in sci emulate patches.
4. x86_64-limit-cpus				 - Limit cpus present to emulate Physical
									   hotplug.
5. sci_emu.patch					 - Code to emulate SCI notify on a object.

Cheers,
ashok