The dvfs headroom was split into its own knob. Update to use it. am: 1499e8335e am: 2f996c547c

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

Change-Id: I98dd5efc1ed8c9ea8b3388300979e47a63d643f4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>