iommu/qcom: Fix local_base status check

The function qcom_iommu_device_probe() does not perform sufficient
error checking after executing devm_ioremap_resource(), which can
result in crashes if a critical error path is encountered.

Fixes: 0ae349a ("iommu/qcom: Add qcom_iommu")
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200418134703.1760-1-tangbin@cmss.chinamobile.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: Tang Bin

drivers/iommu/qcom_iommu.c

@@ -824,8 +824,11 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
 	qcom_iommu->dev = dev;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (res)
+	if (res) {
 		qcom_iommu->local_base = devm_ioremap_resource(dev, res);
+		if (IS_ERR(qcom_iommu->local_base))
+			return PTR_ERR(qcom_iommu->local_base);
+	}
 
 	qcom_iommu->iface_clk = devm_clk_get(dev, "iface");
 	if (IS_ERR(qcom_iommu->iface_clk)) {