cxgb4vf: fix bug in Generic Receive Offload

Fix botch in Generic Receive Offload (the Packet Gather List Total length
field wasn't being initialized).
Signed-off-by: NCasey Leedom <leedom@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/cxgb4vf/sge.c

@@ -1679,6 +1679,7 @@ int process_responses(struct sge_rspq *rspq, int budget)
 				}
 				len = RSPD_LEN(len);
 			}
+			gl.tot_len = len;
 
 			/*
 			 * Gather packet fragments.