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: I9fc9646f222d738b9daf16566abfcac33b842116
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>