becd984900
When the guest is bringing up the APs in the x2APIC mode a write to the ICR register will now trigger a return to userspace with an exitcode of VM_EXITCODE_SPINUP_AP. This gets SMP guests working again with x2APIC. Change the vlapic timer lock to be a spinlock because the vlapic can be accessed from within a critical section (vm run loop) when guest is using x2apic mode. Reviewed by: grehan@