scsi: ufs: ufs-exynos: Fix return value check in exynos_ufs_init()

In case of error, the function devm_ioremap_resource() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should be
replaced with IS_ERR().

Link: https://lore.kernel.org/r/20200618133837.127274-1-weiyongjun1@huawei.com
Fixes: 55f4b1f7 ("scsi: ufs: ufs-exynos: Add UFS host support for Exynos SoCs")
Reported-by: Hulk Robot <hulkci@huawei.com>
Acked-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs-exynos.c

@@ -950,25 +950,25 @@ static int exynos_ufs_init(struct ufs_hba *hba)
 	/* exynos-specific hci */
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "vs_hci");
 	ufs->reg_hci = devm_ioremap_resource(dev, res);
-	if (!ufs->reg_hci) {
+	if (IS_ERR(ufs->reg_hci)) {
 		dev_err(dev, "cannot ioremap for hci vendor register\n");
-		return -ENOMEM;
+		return PTR_ERR(ufs->reg_hci);
 	}
 
 	/* unipro */
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "unipro");
 	ufs->reg_unipro = devm_ioremap_resource(dev, res);
-	if (!ufs->reg_unipro) {
+	if (IS_ERR(ufs->reg_unipro)) {
 		dev_err(dev, "cannot ioremap for unipro register\n");
-		return -ENOMEM;
+		return PTR_ERR(ufs->reg_unipro);
 	}
 
 	/* ufs protector */
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ufsp");
 	ufs->reg_ufsp = devm_ioremap_resource(dev, res);
-	if (!ufs->reg_ufsp) {
+	if (IS_ERR(ufs->reg_ufsp)) {
 		dev_err(dev, "cannot ioremap for ufs protector register\n");
-		return -ENOMEM;
+		return PTR_ERR(ufs->reg_ufsp);
 	}
 
 	ret = exynos_ufs_parse_dt(dev, ufs);