Add a helper method to generate the IPv6 address based on EUI64. am: 3d0850507e

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/2495761

Change-Id: I8a9378522def4ae675b2028b2784a9b9414cc9b6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>