mailbox: hi3660: Make use of the helper function devm_platform_ioremap_resource()

Use the devm_platform_ioremap_resource() helper instead of
calling platform_get_resource() and devm_ioremap_resource()
separately
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/hi3660-mailbox.c

@@ -240,7 +240,6 @@ static int hi3660_mbox_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct hi3660_mbox *mbox;
 	struct mbox_chan *chan;
-	struct resource *res;
 	unsigned long ch;
 	int err;
 
@@ -248,8 +247,7 @@ static int hi3660_mbox_probe(struct platform_device *pdev)
 	if (!mbox)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	mbox->base = devm_ioremap_resource(dev, res);
+	mbox->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mbox->base))
 		return PTR_ERR(mbox->base);