irqchip/mbigen: Fix memory mapping code

Some mbigens share memory regions, and devm_ioremap_resource
does not allow to share resources which will break the probe
of mbigen, in opposition to devm_ioremap.

This patch restores back usage of devm_ioremap function, but
with proper error handling and logging.

Fixes: 216646e4d82e ("irqchip/mbigen: Fix return value check in mbigen_device_probe()")
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: linuxarm@huawei.com
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: MaJun <majun258@huawei.com>
Link: http://lkml.kernel.org/r/1494561328-39514-2-git-send-email-guohanjun@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/irqchip/irq-mbigen.c

@@ -337,9 +337,12 @@ static int mbigen_device_probe(struct platform_device *pdev)
 	mgn_chip->pdev = pdev;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	mgn_chip->base = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(mgn_chip->base))
-		return PTR_ERR(mgn_chip->base);
+	mgn_chip->base = devm_ioremap(&pdev->dev, res->start,
+				      resource_size(res));
+	if (!mgn_chip->base) {
+		dev_err(&pdev->dev, "failed to ioremap %pR\n", res);
+		return -ENOMEM;
+	}
 
 	if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node)
 		err = mbigen_of_create_domain(pdev, mgn_chip);