ANDROID: GKI: arm64: dma-mapping: add support for IOMMU mapper

On systems with IOMMUs, it's useful to handle IOMMU mappings in the
dma-mapping layer. This is currently supported on arm but not arm64. Add
support in arm64 by gratuitously lifting most of the IOMMU-related stuff
from dma-mapping.c in arm.

The original arm work was done by Marek Szyprowski in [4ce63fcd:
"ARM: dma-mapping: add support for IOMMU mapper"].

Change-Id: I1c3c8fe15049fe456751074398fd179ebd2ec64e
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
Bug: 155522481
Signed-off-by: Mark Salyzyn <salyzyn@google.com>
[saravanak snapshot from commit 79efc458af96 that approximately matches
commit f0dbb6af93e971a24e272267dc6d22676900873d]
Signed-off-by: Saravana Kannan <saravanak@google.com>