Merge branch 'remcsum_adjust'

Tom Herbert says:

====================
gue: Generalize remote checksum offload

The remote checksum offload is generalized by creating a common
function (remcsum_adjust) that does the work of modifying the
checksum in remote checksum offload. This function can be called
from normal or GRO path. GUE was modified to use this function.

Remote checksum offload is described in
https://tools.ietf.org/html/draft-herbert-remotecsumoffload-01



Tested by running 200 TCP_STREAM connections over GUE, did not see
any problems with remote checksum offload enabled.
====================

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