KeyMaster: restore device_unique_attestation

This got accidentally lost during the code review markups on
aosp/1719597 and aosp/1719302

Bug: 186735514
Test: VtsAidlKeyMintTargetTest
Merged-In: I3fafe44371e5b436e4c6e4c1454f2970fc6425ba
Change-Id: I3fafe44371e5b436e4c6e4c1454f2970fc6425ba
Ignore-AOSP-First: already present in aosp/master
1 file changed