schemas: Deduplicate cpuTopology in cputypes.rng

schemas: Deduplicate cpuTopology in cputypes.rng

The duplicate had the "dies" attribute missing, causing
  $ virsh capabilities > cap.xml
  $ virsh [hypervisor-]cpu-compare cap.xml --validate
to fail with
  error: Failed to compare hypervisor CPU with cap.xml
  error: XML document failed to validate against schema: Unable to validate doc against /usr/share/libvirt/schemas/cpu.rng
  Invalid attribute dies for element topology

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