Commit b8a1bb1dd215 (pci: defer device registration until after bridge setup)
changed the activation order of devices, so that bridges above the devices could
be configured properly before activating the devices below. This commit failed
to acknowledge that there may be devices located directly on the root bus without
any bridge in between and so those devices would never get enabled.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>