iommu/arm-smmu: add devices attached to the SMMU to an IOMMU group

IOMMU groups are expected by certain users of the IOMMU API,
e.g. VFIO. Add new devices found by the SMMU driver to an IOMMU
group to satisfy those users.

Change-Id: I3614e02eff7540a9c9b6c09224df19d23f3f6800
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Git-commit: 5fc63a7c446e998d01a68b108fe007be675aced7
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>