Merge branch 'Add bpf programmable net device'

Daniel Borkmann says:

====================
This work adds a BPF programmable device which can operate in L3 or L2
mode where the BPF program is part of the xmit routine. It's program
management is done via bpf_mprog and it comes with BPF link support.
For details see patch 1 and following. Thanks!

v3 -> v4:
  - Moved netkit_release_all() into ndo_uninit (Stan)
  - Two small commit msg corrections (Toke)
  - Added Acked/Reviewed-by
v2 -> v3:
  - Remove setting dev->min_mtu to ETH_MIN_MTU (Andrew)
  - Do not populate ethtool info->version (Andrew)
  - Populate netdev private data before register_netdevice (Andrew)
  - Use strscpy for ifname template (Jakub)
  - Use GFP_KERNEL_ACCOUNT for link kzalloc (Jakub)
  - Carry and dump link attach type for bpftool (Toke)
v1 -> v2:
  - Rename from meta (Toke, Andrii, Alexei)
  - Reuse skb_scrub_packet (Stan)
  - Remove IFF_META and use netdev_ops (Toke)
  - Add comment to multicast handler (Toke)
  - Remove silly version info (Toke)
  - Fix attach_type_name (Quentin)
  - Rework libbpf link attach api to be similar
    as tcx (Andrii)
  - Move flags last for bpf_netkit_opts (Andrii)
  - Rebased to bpf_mprog query api changes
  - Folded link support patch into main one
====================

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>