PCI/VPD: Treat invalid VPD like missing VPD capability

Exporting sysfs files that can't be accessed doesn't make much sense.
Therefore, if either a quirk or the dynamic size calculation result in VPD
being marked as invalid, treat this as though the device has no VPD
capability.  One consequence is that the "vpd" sysfs file is not visible.

Link: https://lore.kernel.org/r/6a02b204-4ed2-4553-c3b2-eacf9554fa8d@gmail.com


Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>