Revert "only enable APFv6 ND offload if preloaded"

This reverts commit 43acd988da950d6d8cc7b664a300b5ca058f4646.

Reason for revert: As discussed, we don't create additional method to turn on the feature. 

Change-Id: I6e9889631c62ba7acb2fe6a85d14d2a0ce7be26f
4 files changed