iommu/arm-smmu: Implement ->probe_finalize()

Implement a ->probe_finalize() callback that can be used by vendor
implementations to perform extra programming necessary after devices
have been attached to the SMMU.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20210603164632.1000458-4-thierry.reding@gmail.com


Signed-off-by: Will Deacon <will@kernel.org>