PCI: Convert pci_dev_flags definitions to bit shifts

Convert the pci_dev_flags definitions from decimal constants to bit shifts.
We're only a few entries away from where using the decimal value becomes
cumbersome.  No functional change.

Tested-by: George Spelvin <linux@horizon.com>
Tested-by: Pat Erley <pat-lkml@erley.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>