iommu/arm-smmu: Support non-strict mode

iommu/arm-smmu: Support non-strict mode

BugLink: https://bugs.launchpad.net/bugs/1806488
All we need is to wire up .flush_iotlb_all properly and implement the
domain attribute, and iommu-dma and io-pgtable will do the rest for us.
The only real subtlety is documenting the barrier semantics we're
introducing between io-pgtable and the drivers for non-strict flushes.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
(backported from commit 44f6876a00e83df5fd28681502b19b0f51e4a3c6)
[ dannf: trivial context fix in arm_smmu_ops struct ]
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>