Merge branch 'virtio_net-xdp-refine'

Jason Wang says:

====================
Refine virtio-net XDP

This series brings two optimizations for virtio-net XDP:

- avoid reset during XDP set
- turn off offloads on demand

Changes from V1:
- Various tweaks on commit logs and comments
- Use virtnet_napi_enable() when enabling NAPI on XDP set
- Copy the small buffer packet only if xdp_headroom is smaller than
  required
====================

Signed-off-by: David S. Miller <davem@davemloft.net>