The xenbus module provides xenbus_map_ring_valloc() and
xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
granted by the frontend.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>