pvmdice: Add sign_data

Bug: 369146791
Test: trusty/vendor/google/aosp/scripts/build.py \
        qemu-generic-arm64-test-debug \
        --test="boot-test:com.android.trusty.rust.pvmdice.test"

Change-Id: I819ac4e35d35d1d507ea4817875cec520899a198
6 files changed