In case we are passed an "odev" (a device to start the search from),
that device would have an extra reference. The best way to illustrate
this is to look at for_each_pci_dev() which will return one device
after the other. Upon first return we return a pdev with a reference.
That pdev is then passed in as odev on the next call. If we do not
clear the reference it will be leaked.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Fixes: 910cf345d0ee9 ("LinuxKPI: pci: implement ...")