x86, apic: Remove check_apicid_present callback

The check_apicid_present() apic callback is never called, so remove it
and functions that implement it.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302350160.17503@chino.kir.corp.google.com


Signed-off-by: H. Peter Anvin <hpa@zytor.com>