msm: kgsl: Change iommu structure to better represent the hardware

Change the iommu structures to properly represent the iommu hardware
which makes the code more readable.

Change-Id: I61cf988998da3fc4f62ca020e4240cf50ddd20f0
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>
6 files changed