Merge branch 'xen-netback-rx-refactor'

Merge branch 'xen-netback-rx-refactor'

Paul Durrant says:

====================
xen-netback: guest rx side refactor

This series refactors the guest rx side of xen-netback:

- The code is moved into its own source module.

- The prefix variant of GSO handling is retired (since it is no longer
  in common use, and alternatives exist).

- The code is then simplified and modifications made to improve
  performance.

v2:
- Rebased onto refreshed net-next
====================

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