mailbox: altera: 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 <[e-mail]>
Signed-off-by: Jassi Brar <[e-mail]>

drivers/mailbox/mailbox-altera.c

···
 static int altera_mbox_probe(struct platform_device *pdev)
 {
 	struct altera_mbox *mbox;
-	struct resource	*regs;
 	struct mbox_chan *chans;
 	int ret;
 
···
 	if (!chans)
 		return -ENOMEM;
 
-	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-
-	mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
+	mbox->mbox_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mbox->mbox_base))
 		return PTR_ERR(mbox->mbox_base);