domain_validate: Properly terminate switch() in virDomainIOMMUDefValidate()
domain_validate: Properly terminate switch() in virDomainIOMMUDefValidate()

In my previous commit I've introduced virDomainIOMMUDefValidate()
function with a switch() statement. However, two cases in it,
though empty, were not terminated with a break statement which
made compiler complain.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

crobinso/libvirt,olafhering/libvirt,crobinso/libvirt,zippy2/libvirt,olafhering/libvirt,crobinso/libvirt,olafhering/libvirt,zippy2/libvirt,zippy2/libvirt,jfehlig/libvirt,libvirt/libvirt,libvirt/libvirt,jfehlig/libvirt,jfehlig/libvirt,jfehlig/libvirt,libvirt/libvirt,libvirt/libvirt,crobinso/libvirt,olafhering/libvirt,zippy2/libvirt