bpf offload - make sure bpf code can access packet headers am: 8e69ec111f am: 3129be7a3b am: e762de5deb

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1622559

Change-Id: I7d090f7be7dca15ff4ad2486687a620951dfa2bf