Add bpttool to the trout source tree am: 37dda220a3

Original change: https://android-review.googlesource.com/c/device/google/trout/+/2322591

Change-Id: I304d58d18daddbc00e202725813ba9b1ece9298d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>