Implement HMAC clear key import am: 2df2b27d9c

Original change: https://android-review.googlesource.com/c/trusty/app/sample/+/3344347

Change-Id: I61137e784883da61eae9e603ea9b5bbfbaa4709f
Signed-off-by: Automerger Merge Worker <[email protected]>