core, engine: Do not count sPAPR VLAN devices as PCI

The checkPciAndIdeLimits function accounted sPAPR VLAN devices as PCI,
but these devices have their own bus (the spapr-vio bus). This change
skips these devices in the total count of PCI devices done in the VM
related commands.

Change-Id: Iab14ae25f59cd77e29ef444bb1887911a2dcdb05
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1076518
Signed-off-by: Vitor de Lima <vitor.lima@eldorado.org.br>