cpmac: use resource_size()

The original code is off by one because we should start counting at
zero.  So the size of the resource is end - start + 1.  I switched it to
use resource_size() to do the calculation.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/cpmac.c

@@ -964,7 +964,7 @@ static int cpmac_open(struct net_device *dev)
 	struct sk_buff *skb;
 
 	mem = platform_get_resource_byname(priv->pdev, IORESOURCE_MEM, "regs");
-	if (!request_mem_region(mem->start, mem->end - mem->start, dev->name)) {
+	if (!request_mem_region(mem->start, resource_size(mem), dev->name)) {
 		if (netif_msg_drv(priv))
 			printk(KERN_ERR "%s: failed to request registers\n",
 			       dev->name);
@@ -972,7 +972,7 @@ static int cpmac_open(struct net_device *dev)
 		goto fail_reserve;
 	}
 
-	priv->regs = ioremap(mem->start, mem->end - mem->start);
+	priv->regs = ioremap(mem->start, resource_size(mem));
 	if (!priv->regs) {
 		if (netif_msg_drv(priv))
 			printk(KERN_ERR "%s: failed to remap registers\n",
@@ -1049,7 +1049,7 @@ static int cpmac_open(struct net_device *dev)
 	iounmap(priv->regs);
 
 fail_remap:
-	release_mem_region(mem->start, mem->end - mem->start);
+	release_mem_region(mem->start, resource_size(mem));
 
 fail_reserve:
 	return res;
@@ -1077,7 +1077,7 @@ static int cpmac_stop(struct net_device *dev)
 	free_irq(dev->irq, dev);
 	iounmap(priv->regs);
 	mem = platform_get_resource_byname(priv->pdev, IORESOURCE_MEM, "regs");
-	release_mem_region(mem->start, mem->end - mem->start);
+	release_mem_region(mem->start, resource_size(mem));
 	priv->rx_head = &priv->desc_ring[CPMAC_QUEUES];
 	for (i = 0; i < priv->ring_size; i++) {
 		if (priv->rx_head[i].skb) {