Add Bazel BUILD files to BoringSSL.

Android Auto needs these to build its support libraries. BoringSSL's
build-file generator supports Bazel, so this is just a matter of passing
the right option to the generator.

Test: build/bazel/bazel.sh build //external/boringssl:crypto
Fixes: 178776443
Change-Id: I6ee9f72915bc84b297c109fd1931be704161687d
4 files changed