vhost_net: re-enable when cross endian

Cross-endianness is now checked by the core vhost code.

revert 371df9f5 "vhost-net: disable when cross-endian"

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
[ added commit message, Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>