net: xilinx_ethlite: Fix Rx-pong interrupt There is no CTRL_I bit in the pong buffer control register. The CTRL_I bit from the ping buffer masks both ping and pong buffers. Fix. Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>