Skip getting PCI info from disks type USB and give them an empty PCI address instead.

Signed-off-by: Kfir Manor <kfir@daynix.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>