Workload hint handler should lower clock freq if workload does not change

[philburk]

REPRODUCE adb shell synthmark -tj -n16 -w0 adb shell synthmark -tj -n16 -w1

EXPECT Similar render times because load is not changing.

ACTUAL Render times with -n16 are very low indicating high utilization. Also this is printed: workUnits=16 requestDLBandwidth=0.900000 [###########################___]

SynthMark initially sets the utilization very high (90%) so that it can calibrate the workload. But it does not lower the utilization until the workload changes. After the initial calibration, it could check to see if the utilization is set too high and lower it.