drm/msm/gpu: Bypass PM QoS constraint for idle clamp

drm/msm/gpu: Bypass PM QoS constraint for idle clamp

Change idle freq clamping back to the direct method, bypassing PM QoS
requests.  The problem with using PM QoS requests is they call
(indirectly) the governors ->get_target_freq() which goes thru a
get_dev_status() cycle.  The problem comes when the GPU becomes active
again and we remove the idle-clamp request, we go through another
get_dev_status() cycle for the period that the GPU has been idle, which
triggers the governor to lower the target freq excessively.

This partially reverts commit 7c0ffcd40b16 ("drm/msm/gpu: Respect PM QoS
constraints"), but preserves the use of boost QoS request, so that it
will continue to play nicely with other QoS requests such as a cooling
device.  This also mostly undoes commit 78f815c1cf8f ("drm/msm: return the
average load over the polling period")

Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/517785/
Link: https://lore.kernel.org/r/20230110231447.1939101-3-robdclark@gmail.com
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>