PCI/VPD: Remove struct pci_vpd_ops

Some multi-function devices share VPD hardware across functions and don't
work correctly for concurrent VPD accesses to different functions.

Struct pci_vpd_ops was added by 932c435c ("PCI: Add dev_flags bit to
access VPD through function 0") so that on these devices, VPD accesses to
any function would always go to function 0.

It's easier to just check for the PCI_DEV_FLAGS_VPD_REF_F0 quirk bit in the
two places we need it than to deal with the struct pci_vpd_ops.

Simplify the code by removing struct pci_vpd_ops and removing the indirect
calls.

[bhelgaas: check for !func0_dev earlier, commit log]
Link: https://lore.kernel.org/r/b2532a41-df8b-860f-461f-d5c066c819d0@gmail.com


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