Hi Keir and Jan,

This patch is to support the new core pair topology introduced by AMD 
new CPUs, which introduces a new concept of core/compute unit/node. 
There is a new feature bit for topology extension in CPUID:0x80000001. 
Also a new CPUID (0x8000001E) is introduced for CPU topology 
enumeration. This patch collects the sibling information from a new 
CPUID and the info will be stored into the sibling map in Xen.

Please help review it. Comments are welcome.

Signed-off-by: Wei Huang <wei.huang2@amd.com>