net: set endianness on all backend devices

commit 5be7d9f1
       vhost-net: tell tap backend about the vnet endianness

makes vhost net to set the endianness of the device, but only for
the first device.

In case of multiqueue, we have multiple devices... This patch sets the
endianness for all the devices of the interface.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>