iommu: arm-smmu: Add support for ACTLR settings for sdm845

Some MMU500 implementations have additional settings in the ACTLR
register. Retrieve the settings from devicetree and validate that
all devices in the same iommu_group share the same ACTLR settings.

Change-Id: Idbe32ac3b1b6774cfbc9cc5218eb9605a67d0637
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>