From: James Cleverdon <jamesclv@us.ibm.com>

On summit-based machines the cpu_sibling_map data has been hosed for some
time.  I found out why in Intel's IA-32 Software Deveveopers' Manual Vol 2
under CPUID.  Looks like the value that cpuid returns is the one latched at
reset, and doesn't reflect any changes made by the BIOS later:

  * Local APIC ID (high byte of EBX)--this number is the 8-bit ID that
    is assigned to the local APIC on the processor during power up.  This
    field was introduced in the Pentium 4 processor.

Also, the code in init_intel was a bit overdesigned.  Until Intel releases
a chip with a non-power-of-2 sibling count on it, there's no point in all
that bit bashing.