ibmveth: Don't receive packets when the napi budget == 0

Processing any incoming packets with a with a napi budget of 0
is incorrect driver behavior.

This matters as netpoll will shortly call drivers with a budget of 0
to avoid receive packet processing happening in hard irq context.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/ibmveth.c

@@ -1072,7 +1072,7 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 	unsigned long lpar_rc;
 
 restart_poll:
-	do {
+	while (frames_processed < budget) {
 		if (!ibmveth_rxq_pending_buffer(adapter))
 			break;
 
@@ -1121,7 +1121,7 @@ restart_poll:
 			netdev->stats.rx_bytes += length;
 			frames_processed++;
 		}
-	} while (frames_processed < budget);
+	}
 
 	ibmveth_replenish_task(adapter);