Patch from James Cleverdon & John Stultz

Changes IO_APIC_MAX_ID to depend on the APIC type we're using.
The Summit machines have to use a larger set of bits in the apic registers,
we enlarge under ifdef for Summit only. We enlarge MAX_APICS for summit
as well as NUMA-Q (it would be nice to move this to subarch, but it creates
circular dependency problems ... I'll fix this up later).

Adds a check for the newer Summit boxes with a different name.