Add missing @Override to two ILockSettings methods

All ILockSettings methods of LockSettingsService use @Override except
for two.  Add @Override to the two methods that missed it.  This makes
it clear that they are part of LockSettingsService's public interface.

Test: presubmit
Flag: EXEMPT no functional change
Change-Id: I83947d49366a91aff137f8b27dfa96fc4569653a