Merge branch 'nfp-AF_XDP-zero-copy'

Simon Horman says:

====================
Add AF_XDP zero-copy support for NFP

Niklas Söderlund says:

This series adds AF_XDP zero-copy support for the NFP driver. The series
is based on previous work done by Jakub Kicinski.

Patch 1/5 and 2/5 prepares the driver for AF_XDP support by refactoring
functions that will act differently once AF_XDP is active or not making
the driver easier to read and by preparing some functions to be reused
outside the local file scope. Patch 3/5 and 4/5 prepares the driver for
dealing the UMEM while finally patch 5/5 adds AF_XDP support.

Based on work by Jakub Kicinski.
====================

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