Add BPF_LOAD_SKB_PKTTYPE macro to BpfClassic.h am: c58cfb7c7d am: a24a7c4b35

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3364312

Change-Id: I7347e39cee18aefe8d3e86aad6a3c888f4ca2a82
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>