Merge "Update Documentation for EPOCH_TIME." into sc-qpr1-dev am: 922f2b0b am: 828a063f am: cb86f7c6

Original change: https://googleplex-android-review.googlesource.com/c/platform/hardware/interfaces/+/15618006

Change-Id: Ie9b383ce0b8ae67a51cd49b8875f03bd3b67ae75