msm: iommu: Revise GFX2D0 IOMMU contexts and M2V mappings

Based on recommendations from chip designers,
optimize the Machine ID to translation context
mappings for the first 2D core's IOMMU. Remove the
"gfx2d0_texv3_smmu" context, as it is no longer needed
under the new mapping scheme.

Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>