iommu: qti: Track iommu domains

Add a new module to track iommu domains, including those which
may not currently be active. Supports multiple types of smmu
drivers.

Change-Id: Iacb98d823db8a87a2cf0868c467914847351950b
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
[isaacm@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>