utils: bdaddr: Fallback to bootconfig to read serialno am: bd160522bf

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2664198

Change-Id: I897bc60e57c3c8589193995f76dd2de57652fd3b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>