cpu_x86: Require <cpuid> within <feature> in CPU map
cpu_x86: Require <cpuid> within <feature> in CPU map

A feature with no cpuid element is invalid and it should not be silently
treated as a feature with all CPUID bits set to zero.

Signed-off-by: Jiri Denemark <62bdf77dc47919a4d59a91822129d14633cfca81@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

fabianfreyer/libvirt,zippy2/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,eskultety/libvirt,zippy2/libvirt,libvirt/libvirt,andreabolognani/libvirt,nertpinx/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,zippy2/libvirt,crobinso/libvirt,nertpinx/libvirt,libvirt/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,zippy2/libvirt,nertpinx/libvirt,crobinso/libvirt,jardasgit/libvirt,olafhering/libvirt,crobinso/libvirt,jfehlig/libvirt,andreabolognani/libvirt,nertpinx/libvirt,andreabolognani/libvirt,jardasgit/libvirt,andreabolognani/libvirt,libvirt/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,eskultety/libvirt,jardasgit/libvirt,crobinso/libvirt,olafhering/libvirt,eskultety/libvirt,jardasgit/libvirt,eskultety/libvirt,jfehlig/libvirt,olafhering/libvirt,libvirt/libvirt,eskultety/libvirt,olafhering/libvirt