The clients of resume on reboot want additional information for
reboot failures, so they can handle these failures better.
Therefore expose the reboot failure error code via SystemApi.
Bug: 183646725
Test: atest FrameworksServicesTests:RecoverySystemServiceTest;
Do an RoR with gmscore
Change-Id: Ia02655218194a070ce02e9dae6fd62e19259c9f9