The dvfs headroom was split into its own knob. Update to use it. am: 1499e8335e am: e2b18ee947

Original change: https://googleplex-android-review.googlesource.com/c/device/google/raviole/+/23124060

Change-Id: Ia0b0538b269af34f22e5719a759ea16426bded63
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>