drm/msm: Remove obsolete perf infrastructure

drm/msm: Remove obsolete perf infrastructure

Outside of a3xx, this was never really used.  And it low-key gets in the
way of the new perfcntr support (or at least it is confusing to have two
things called "perf").  So lets remove it.

This drops the "perf" debugfs file.  But these days, nvtop is a better
option.  (Plus perfetto for newer gens.)

Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Anna Maniscalco <anna.maniscalco2000@gmail.com>
Reviewed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/728200/
Message-ID: <20260526145137.160554-2-robin.clark@oss.qualcomm.com>