Update AMD CPUID 0x80000001:ECX feature flags

The attached two patches syncs-up AMD CPUID feature flags with the upstream Linux kernel. Note that several new feature bits will be added in new AMD CPUs. In the meanwhile, names of some existing feature flags were changed in Linux.

I split the patch into two parts: one for Xen hypervisor and one for Xen tools. Please review and apply.

Thanks,
-Wei