Merge "Add some more public doc for MacAddress" am: 758d6bd8d0 am: 28d7770303 am: 3b04eba16b am: 526dc71822

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1354447

Change-Id: Idb097086b514c76cd7601d833a5cfaedcdc1e616