PCI/VPD: Remove pci_set_vpd_size()

24a1720a ("cxgb4: collect serial config version from register") removed
the only usage of pci_set_vpd_size(). If a device needs to override the
auto-detected VPD size, then this can be done with a PCI quirk, as is done
for Chelsio devices. There's no need to allow drivers to change the VPD
size.

Remove pci_set_vpd_size().

[bhelgaas: squash in Arnd's fix for "'pci_vpd_set_size' defined but not
used" from
https://lore.kernel.org/r/20210421140334.3847155-1-arnd@kernel.org]
Link: https://lore.kernel.org/r/47d86e52-9bcf-7da7-1edb-0d988a7a82ab@gmail.com


Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Krzysztof Wilczyński <kw@linux.com>