Fix lunch choices for git_main am: 39ed5d7ba3

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2810697

Change-Id: Iad846554c497177fc390c50d9f547f958ac1b59d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>