[ Upstream commit 4ef76ad0 ]

The Ampere Computing PCIe root port does not support ACS at this point.
However, the hardware provides isolation and source validation through the
SMMU. The stream ID generated by the PCIe ports contain both the
bus/device/function number as well as the port ID in its 3 most significant
bits. Turn on ACS but disable all the peer-to-peer features.

APM is being rebranded to Ampere.  The Vendor and Device IDs change, but
the functionality stays the same.

Signed-off-by: Feng Kan <fkan@apm.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>