drm/msm/a6xx: Switch to preemption safe AO counter

drm/msm/a6xx: Switch to preemption safe AO counter

CP_ALWAYS_ON_COUNTER is not save-restored during preemption, so it won't
provide accurate data about the 'submit' when preemption is enabled.
Switch to CP_ALWAYS_ON_CONTEXT which is preemption safe.

Fixes: e7ae83da4a28 ("drm/msm/a6xx: Implement preemption for a7xx targets")
Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/714657/
Message-ID: <20260327-a8xx-gpu-batch2-v2-3-2b53c38d2101@oss.qualcomm.com>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>