Drop ARP packet in APF if the opcode is unknown am: e63d620672

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/2840299

Change-Id: I4adbf17e09561e26bdb53f3b341d544d455da835
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>