iommu/arm-smmu: Add support for page table donation

For secure domains, the page tables need to be assigned
to the correct VMIDs. Add support for doing the assignment.

Change-Id: I60009ef96ae1c8965d57096b6a1b0658ae6acc9a
Signed-off-by: Neeti Desai <neetid@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>