Specify that only output ports need to be positive. am: 4e24d7a342

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

Change-Id: I161ac7205594cc0ed468ccf1fdec43fb363be656
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>