Clean up keymint ProtectedData documentation am: 1d389acec8 am: 19eff513d4 am: 76626c0bda am: 45b3039ebb

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2075940

Change-Id: I14d475ce2d66a285696e9763a4419a95b5434174
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>