Use accessor for EVP_PKEY types am: 39b1ba3702 am: c4f9d05b28 am: f8bdea52f4

Original change: https://android-review.googlesource.com/c/platform/system/keymaster/+/2148656

Change-Id: I6d88b517144af4c63db3bcf33d50c5f54daf6272
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>