The Solarflare SFC9220 apparently lacks an ACS capability, but does not
perform peer-to-peer between functions.  Add a quirk so we know about this
isolation.

[bhelgaas: changelog]
Signed-off-by: NEdward Cree <ecree@solarflare.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>