drm/msm/gpu: Fix check for devices without devfreq

drm/msm/gpu: Fix check for devices without devfreq

Looks like 11da1019051e ("drm/msm/devfreq: Add 1ms delay before
clamping freq") was badly rebased on top of e7d7ad54de97 ("drm/msm:
Fix devfreq NULL pointer dereference on a3xx") and ended up with
the NULL check in the wrong place.

Fixes: 11da1019051e ("drm/msm/devfreq: Add 1ms delay before clamping freq")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20211120200103.1051459-2-robdclark@gmail.com
Signed-off-by: Rob Clark <robdclark@chromium.org>