enic: fix work done in tx napi_poll

With the commit d75b1ade567 ("net: less interrupt masking in NAPI") napi repoll
is done only when work_done == budget. In tx napi poll we always return 0.
So tx napi is not called again and we do not clean up the tx ring.

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cisco/enic/enic_main.c

@@ -1312,9 +1312,10 @@ static int enic_poll_msix_wq(struct napi_struct *napi, int budget)
 	if (!wq_work_done) {
 		napi_complete(napi);
 		vnic_intr_unmask(&enic->intr[intr]);
+		return 0;
 	}
 
-	return 0;
+	return budget;
 }
 
 static int enic_poll_msix_rq(struct napi_struct *napi, int budget)