msm: kgsl: redo iommu self programming

Use attributes from the iommu domain to retrieve proper TTBR0 and
CONTEXTIDR values, rather than reading registers and using our
own field masks.

Use the DYNAMIC attribute when creating per-process domains.
This allows the iommu driver to configure the domain's pagetable
before we create mappings. It also allows the iommu driver to issue
TLBI command during iommu_unmap calls for a per-process domain.
This removes the need for dodgy TLBIALL commands from kgsl after
iommu_unmap() returns.

Change-Id: Ie3a24a1ae9fb768d78c6ec18ab739e689c4d8f32
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>