There are sometimes gerrit warnings on Android.bp file format:
```
Analyzer Description: Formats Android.bp files.
Owner: soong-team@google.com

This file is not formatted.

Run prebuilts/build-tools/linux-x86/bin/bpfmt -w {filename} to format the file, or apply the suggested fix.
```

This commit adds the suggested format script to make-pretty.sh to avoid
the warning.

Change-Id: I8a691b1e6af873e8c43e34ed3168203d469eee1c