Merge branch 'virtio_net-GSO-helpers'

Mike Rapoport says:

====================
virtio_net: use common code for virtio_net_hdr and skb GSO conversion

This patches introduce virtio_net_hdr_{from,to}_skb functions for
conversion of GSO information between skb and virtio_net_hdr.
====================

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