net/nfp: fix Rx descriptor DMA address

When receiving a packet that is larger than the mbuf size, the Rx
function will break the receive loop and sent a free list descriptor
with random DMA address.

Fix this by moving the increment of the free list descriptor counter
to after the packet size have been checked and acted on.

Fixes: bb340f5 ("net/nfp: fix memory leak in Rx")
Cc: stable@dpdk.org

Signed-off-by: Chaoyong He <chaoyong.he@corigine.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com>

drivers/net/nfp/nfp_rxtx.c

@@ -293,8 +293,6 @@ nfp_net_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 			break;
 		}
 
-		nb_hold++;
-
 		/*
 		 * Grab the mbuf and refill the descriptor with the
 		 * previously allocated mbuf
@@ -365,6 +363,7 @@ nfp_net_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 		rxds->fld.dd = 0;
 		rxds->fld.dma_addr_hi = (dma_addr >> 32) & 0xff;
 		rxds->fld.dma_addr_lo = dma_addr & 0xffffffff;
+		nb_hold++;
 
 		rxq->rd_p++;
 		if (unlikely(rxq->rd_p == rxq->rx_count)) /* wrapping?*/