cpu_map: Add libcpuinfo as optional data source

cpu_map: Add libcpuinfo as optional data source

This adds an option to use libcpuinfo [1] as data source for
libvirt's list of x86 cpu features. This is purely optional and
does not change the script's behavior if libcpuinfo is not
installed.

libcpuinfo is a cross-vendor, cross-architecture source for CPU
related information that has the capability to replace libvirt's
dependence on qemu's cpu feature list.

[1] https://gitlab.com/twiederh/libcpuinfo

Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>