PCI: Add ACS quirk for Wangxun FF5xxx NICs

PCI: Add ACS quirk for Wangxun FF5xxx NICs

Wangxun FF5xxx NICs are similar to SFxxx, RP1000 and RP2000 NICs.  They may
be multi-function devices, but they do not advertise an ACS capability.

But the hardware does isolate FF5xxx functions as though it had an ACS
capability and PCI_ACS_RR and PCI_ACS_CR were set in the ACS Control
register, i.e., all peer-to-peer traffic is directed upstream instead of
being routed internally.

Add ACS quirk for FF5xxx NICs in pci_quirk_wangxun_nic_acs() so the
functions can be in independent IOMMU groups.

Link: https://lore.kernel.org/r/E16053DB2B80E9A5+20241115024604.30493-1-mengyuanlou@net-swift.com
Signed-off-by: Mengyuan Lou <mengyuanlou@net-swift.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>