ANDROID: KVM: arm64: iommu: Reduce the logic in generic code

SMMUv3 page-table library requires special locking, instead of having
it’s specific solution or constraints part of the IOMMU generic
framework, introduce new driver ops (map/unmap/iova_to_phys) which can
implement that.

This simplifies the IOMMU code to only manage refcounts and provides
guarantees that the domain can’t be freed while used.

This is also helpful as KMI is approaching, which makes SMMUv3 changes
isolated in its module.

Bug: 277989609
Bug: 278749606

Change-Id: I0ae3d2ef7455a4438a43454c43f29750f49efab6
Signed-off-by: Mostafa Saleh <smostafa@google.com>