https://bugzilla.redhat.com/show_bug.cgi?id=998813

Like usb-serial, the pci-serial device allows a serial device to be
attached to PCI bus. An example XML looks like this:

  <serial type='dev'>
    <source path='/dev/ttyS2'/>
    <target type='pci-serial' port='0'/>
    <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
  </serial>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>