bna: fix performance regression

The recent commit "e29aa33 bna: Enable Multi Buffer RX" is causing
a performance regression. It does not properly update 'cmpl' pointer
at the end of the loop in NAPI handler bnad_cq_process(). The result is
only one packet / per NAPI-schedule is processed.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/brocade/bna/bnad.c b/drivers/net/ethernet/brocade/bna/bnad.c
index 3a77f9e..556aab7 100644
--- a/drivers/net/ethernet/brocade/bna/bnad.c
+++ b/drivers/net/ethernet/brocade/bna/bnad.c
@@ -600,9 +600,9 @@
 	prefetch(bnad->netdev);
 
 	cq = ccb->sw_q;
-	cmpl = &cq[ccb->producer_index];
 
 	while (packets < budget) {
+		cmpl = &cq[ccb->producer_index];
 		if (!cmpl->valid)
 			break;
 		/* The 'valid' field is set by the adapter, only after writing