PCI: Limit config space size for Netronome NFP4000

Like the NFP6000, the NFP4000 as an erratum where reading/writing to PCI
config space addresses above 0x600 can cause the NFP to generate PCIe
completion timeouts.

Limit the NFP4000's PF's config space size to 0x600 bytes as is already
done for the NFP6000.

The NFP4000's VF is 0x6004 (PCI_DEVICE_ID_NETRONOME_NFP6000_VF), the same
device ID as the NFP6000's VF.  Thus, its config space is already limited
by the existing use of quirk_nfp6000().

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>