this accross suspend/resume events and this was causing the dreaded false
positive hit on my "static bug" test.
Note: the PCI bus code should do this for us.
Note2: We don't do the same for I/O based pci devices since it is
more code and doesn't appear to be necessary.
Submitted by: Toshiyuki Kawashima-san <tos@fa2.so-net.ne.jp>
Obtained from: bsd-nomads:16012