x86_64: make k8topology multi-core aware

This makes k8topology multicore aware instead of limited to signle- and
dual-core CPUs.  It uses the CPUID to be more future proof.

Signed-off-by: Joachim Deguara <joachim.deguara@amd.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>