Fix -Wunused-variable compiler warning am: 810d41a774 am: c10d57af29

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2861356

Change-Id: I773425c27d537313208196f63482d50b2d71b497
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>