trusty: cast_auth: fix build with SDK updates am: 80b452d031 am: 5ec99a184b

Original change: https://android-review.googlesource.com/c/trusty/app/cast-auth/+/3142303

Change-Id: I03177c7680fe6c11477e56e7c6eba71e8c20427d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>