iommu/msm: Add DT adaptation

The driver currently works based on platform data. Remove this
and add support for DT. A single master can have multiple ports
connected to more than one iommu.

                      master
                        |
                        |
                        |
           ------------------------
           |                      |
         IOMMU0                 IOMMU1
           |                      |
      ctx0   ctx1            ctx0   ctx1

This association of master and iommus/contexts were previously
represented by platform data parent/child device details. The client
drivers were responsible for programming all of the iommus/contexts
for the device. Now while adapting to generic DT bindings we maintain the
list of iommus, contexts that each master domain is connected to and
program all of them on attach/detach.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Tested-by: Archit Taneja <architt@codeaurora.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>