qemu: Allow migration with invtsc if tsc frequency is set
qemu: Allow migration with invtsc if tsc frequency is set

Migration with invtsc is allowed by QEMU as long as TSC frequency is
explicitly specified.

Signed-off-by: Jiri Denemark <62bdf77dc47919a4d59a91822129d14633cfca81@redhat.com>

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