qemu.pci_devices: Remove incorrect configuration

Remove variant which doesn't follow PCI specification.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

qemu/tests/cfg/pci_devices.cfg

@@ -40,10 +40,6 @@
                     test_setup = "root->bridge->switch->devices"
                 - root_bridge_switch_switch:
                     test_setup = "root->bridge->switch->switch->devices"
-                - root_parallel_root_bridge_switch:
-                    test_setup = "root->devices\n"
-                    test_setup += "   ->bridge->devices\n"
-                    test_setup += "   ->bridge->switch->devices"
     variants:
         - xhci_controller:
             test_device_type = xhci