drm/msm/devfreq: Fix OPP refcnt leak

Reported-by: Douglas Anderson <dianders@chromium.org>
Fixes: 9bc95570

 ("drm/msm: Devfreq tuning")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-By: Steev Klimaszewski <steev@kali.org>
Reviewed-by: Akhil P Oommen <akhilpo@codeaurora.org>
Link: https://lore.kernel.org/r/20211105202021.181092-1-robdclark@gmail.com


Signed-off-by: Rob Clark <robdclark@chromium.org>