PCI/PM: Do not restore BARs if device is not in D0

Do not attempt to restore the device's BARs in
pci_set_full_power_state() if the actual current
power state of the device is not D0.

Link: https://lore.kernel.org/r/1849718.CQOukoFCf9@kreacher


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>