bpf: move BPF_(DIS)ALLOW from block.c to bpf_net_helpers.h am: 1745e54d5d

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3226107

Change-Id: If0745e87c6e41f27e2242af127bb0c4bae6b1e2d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>