BugLink: http://bugs.launchpad.net/bugs/1547674

The XL722 has support for providing the outer UDP tunnel checksum on
transmits.  Make use of this feature to support segmenting UDP tunnels with
outer checksums enabled.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from net-next commit 5453205c)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>