Multiple race conditions are possible between the cardbus PCI device
addition and removal and the generic PCI bus rescan and device removal that
can be triggered via sysfs.

To avoid those race conditions make the cardbus code use global PCI
rescan-remove locking.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>