UPSTREAM: drm/msm/a6xx: Serialize GMU communication

I've seen some crashes in our crash reporting that *look* like multiple
threads stomping on each other while communicating with GMU.  So wrap
all those paths in a lock.

Signed-off-by: Rob Clark <robdclark@chromium.org>
(cherry picked from commit f6f59072e821901d96c791864a07d57d8ec8d312
 https://gitlab.freedesktop.org/drm/msm.git msm-next)

BUG=b:201582820
TEST=boot coachz

Change-Id: I4b2b1c7faddda4134b57f5f5f4a23f40f7c317d0
Disallow-Recycled-Builds: test-failures
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3198978
Tested-by: Rob Clark <robdclark@chromium.org>
Auto-Submit: Rob Clark <robdclark@chromium.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@chromium.org>
Commit-Queue: Rob Clark <robdclark@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3237184
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
3 files changed