mailbox: stm32-ipcc: 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/stm32-ipcc.c

···
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	struct stm32_ipcc *ipcc;
-	struct resource *res;
 	unsigned long i;
 	int ret;
 	u32 ip_ver;
···
 	}
 
 	/* regs */
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	ipcc->reg_base = devm_ioremap_resource(dev, res);
+	ipcc->reg_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(ipcc->reg_base))
 		return PTR_ERR(ipcc->reg_base);