Specify that only output ports need to be positive. am: 4e24d7a3 am: 9891d4a5 am: 7ddc4c11

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2401152



Change-Id: Iebe94da50c2e2c73527530af4fda6f1e2dd5161f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>