Cleanup the last pixel3_mainline reference am: 4714ee4dc0 am: 222eb0c053

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2004160

Change-Id: Ie173cc85e860e0d081735b1d4d2a7472fb0c6d4a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>