Implementing kmr_ta::device::RetrieveKeyMaterial trait

Implementation of root_kek, kak and kek_context functions of
kmr_ta::device::RetrieveKeyMaterial trait.

Bug: 253948020
Test: Build.py, run keymint TA unittests
Change-Id: If48208ea779faf00d742f0c12dbad70678fba7ce
4 files changed
tree: 28dcb5d9325055e3be887e0e294843bad17018ec
  1. app/
  2. keys.rs
  3. lib.rs
  4. main.rs
  5. manifest.json
  6. PREUPLOAD.cfg
  7. rules.mk
  8. usertests-inc.mk