drm/msm: support multiple address spaces

We can have various combinations of 64b and 32b address space, ie. 64b
CPU but 32b display and gpu, or 64b CPU and GPU but 32b display.  So
best to decouple the device iova's from mmap offset.

CRs-Fixed: 2050484
Change-Id: Ic0dedbad2b36b535df3e8fb2ddddc20add592cea
Signed-off-by: Rob Clark <robdclark@gmail.com>
Git-commit: 22877bcbdacd50d076f9b2f829e6a3753aa9821f
Git-repo: https://github.com/freedreno/kernel-msm.git


[jcrouse@codeaurora.org: Fix merge conflicts, remove mdp5 due to large
infrastructure changes, compile fixes]
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
[kabhijit@codeaurora.org: Fix merge conflicts, add support for SDE,
compile fixes]
Signed-off-by: Abhijit Kulkarni <kabhijit@codeaurora.org>