Fixes for v6.12

Display:
- move CRTC resource assignment to atomic_check otherwise to make
  consecutive calls to atomic_check() consistent
- fix rounding / sign-extension issues with pclk calculation in
  case of DSC
- cleanups to drop incorrect null checks in dpu snapshots
- fix to use kvzalloc in dpu snapshot to avoid allocation issues
  in heavily loaded system cases
- Fix to not program merge_3d block if dual LM is not being used
- Fix to not flush merge_3d block if its not enabled otherwise
  this leads to false timeouts

GPU:
- a7xx: add a fence wait before SMMU table update

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/CAF6AEGsp3Zbd_H3FhHdRz9yCYA4wxX4SenpYRSk=Mx2d8GMSuQ@mail.gmail.com