slimbus: qcom: Fix return value check in qcom_slim_probe()

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().
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/slimbus/qcom-ctrl.c

@@ -529,9 +529,9 @@ static int qcom_slim_probe(struct platform_device *pdev)
 
 	slim_mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ctrl");
 	ctrl->base = devm_ioremap_resource(ctrl->dev, slim_mem);
-	if (!ctrl->base) {
+	if (IS_ERR(ctrl->base)) {
 		dev_err(&pdev->dev, "IOremap failed\n");
-		return -ENOMEM;
+		return PTR_ERR(ctrl->base);
 	}
 
 	sctrl->set_laddr = qcom_set_laddr;