net: axienet: Fix compilation warnings

Warning log:
xilinx_axienet_main.c: In function 'axienet_start_xmit_done':
xilinx_axienet_main.c:617:16: warning: operation on 'lp->tx_bd_ci' may be undefined [-Wsequence-point]
xilinx_axienet_main.c: In function 'axienet_start_xmit':
xilinx_axienet_main.c:703:18: warning: operation on 'lp->tx_bd_tail' may be undefined [-Wsequence-point]
xilinx_axienet_main.c:719:17: warning: operation on 'lp->tx_bd_tail' may be undefined [-Wsequence-point]
xilinx_axienet_main.c: In function 'axienet_recv':
xilinx_axienet_main.c:792:16: warning: operation on 'lp->rx_bd_ci' may be undefined [-Wsequence-point]
xilinx_axienet_main.c: In function 'axienet_of_probe':
xilinx_axienet_main.c:1501:21: warning: unused variable 'rc' [-Wunused-variable]
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -601,7 +601,8 @@ static void axienet_start_xmit_done(struct net_device *ndev)
 		size += status & XAXIDMA_BD_STS_ACTUAL_LEN_MASK;
 		packets++;
 
-		lp->tx_bd_ci = ++lp->tx_bd_ci % TX_BD_NUM;
+		++lp->tx_bd_ci;
+		lp->tx_bd_ci %= TX_BD_NUM;
 		cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
 		status = cur_p->status;
 	}
@@ -687,7 +688,8 @@ static int axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 				     skb_headlen(skb), DMA_TO_DEVICE);
 
 	for (ii = 0; ii < num_frag; ii++) {
-		lp->tx_bd_tail = ++lp->tx_bd_tail % TX_BD_NUM;
+		++lp->tx_bd_tail;
+		lp->tx_bd_tail %= TX_BD_NUM;
 		cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
 		frag = &skb_shinfo(skb)->frags[ii];
 		cur_p->phys = dma_map_single(ndev->dev.parent,
@@ -703,7 +705,8 @@ static int axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	tail_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
 	/* Start the transfer */
 	axienet_dma_out32(lp, XAXIDMA_TX_TDESC_OFFSET, tail_p);
-	lp->tx_bd_tail = ++lp->tx_bd_tail % TX_BD_NUM;
+	++lp->tx_bd_tail;
+	lp->tx_bd_tail %= TX_BD_NUM;
 
 	return NETDEV_TX_OK;
 }
@@ -775,7 +778,8 @@ static void axienet_recv(struct net_device *ndev)
 		cur_p->status = 0;
 		cur_p->sw_id_offset = (u32) new_skb;
 
-		lp->rx_bd_ci = ++lp->rx_bd_ci % RX_BD_NUM;
+		++lp->rx_bd_ci;
+		lp->rx_bd_ci %= RX_BD_NUM;
 		cur_p = &lp->rx_bd_v[lp->rx_bd_ci];
 	}