linux-phytec-ti

iommu/omap: add support to program multiple iommus

A client user instantiates and attaches to an iommu_domain
to program the IOMMU associated with the domain. The iommus
programmed by a client user are bound with the iommu_domain
through the user's device archdata. The OMAP IOMMU driver
currently supports only one IOMMU per IOMMU domain per
user.

The OMAP IOMMU driver has been enhanced to support allowing
multiple IOMMUs to be programmed by a single client user. This
support is being added mainly to handle the DSP subsystems in
the DRA7xx SoCs, which have two MMUs within the same subsystem.
These MMUs provide translations to a processor core port and
an EDMA port. This support allows both the MMUs to be programmed
together, but with each one retaining it's own internal state
objects.

The multiple iommus are expected to be provided through a
sentinel terminated array of omap_iommu_archdata objects
through the client user's device archdata. The OMAP driver
core is enhanced to loop through the array of attached
iommus and program them for all common operations.

NOTE:
1. The dev_to_omap_iommu() macro which operates on a device's
   archdata is not adjusted, as its current users can work
   without any additional changes. The OMAP iommu debug code
   relies on operating on each individual iommu object.
2. OMAP IOMMU driver no longer supports non-DT devices or users.
   The reliance on omap_iommu_archdata structure can be
   simplified as the dependence on IOMMU names vanishes with
   non-DT support. The conversion to sentinel-terminated form
   is done automatically for now for DT-based devices that still
   leverage the IOMMU device name.

Signed-off-by: Suman Anna <s-anna@ti.com>