drm/msm: Fix a5xx/a6xx timestamps

They were reading a counter that was configured to ALWAYS_COUNT (ie.
cycles that the GPU is doing something) rather than ALWAYS_ON.  This
isn't the thing that userspace is looking for.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Acked-by: Jordan Crouse <jordan@cosmicpenguin.net>
Message-Id: <20210325012358.1759770-2-robdclark@gmail.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>