mailbox: imx: use devm_platform_ioremap_resource() to simplify code

Use the new helper devm_platform_ioremap_resource() which wraps the
platform_get_resource() and devm_ioremap_resource() together, to
simplify the code.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/imx-mailbox.c

@@ -264,7 +264,6 @@ static int imx_mu_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
-	struct resource *iomem;
 	struct imx_mu_priv *priv;
 	unsigned int i;
 	int ret;
@@ -275,8 +274,7 @@ static int imx_mu_probe(struct platform_device *pdev)
 
 	priv->dev = dev;
 
-	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	priv->base = devm_ioremap_resource(&pdev->dev, iomem);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);