Remove es7000_cpu_mask_to_apicid_cluster completely, because it's
almost the same as es7000_cpu_mask_to_apicid except 2 code paths.
One of them is about to be removed soon, the another should be
BAD_APICID (it's a fail path).
The _cluster one was not invoked on apic->cpu_mask_to_apicid_and
anyway, since there was no _cluster_and variant.