Accept multi-prefixes on receiving DHCPv6 packet. am: 3d4ba042cd

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/2840296

Change-Id: I5a141f187cf535881b3ef614d6f35a2776769526
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>