remoteproc: qcom: wcnss: Fix return value check in wcnss_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: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/qcom_wcnss.c

@@ -528,8 +528,8 @@ static int wcnss_probe(struct platform_device *pdev)
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pmu");
 	mmio = devm_ioremap_resource(&pdev->dev, res);
-	if (!mmio) {
-		ret = -ENOMEM;
+	if (IS_ERR(mmio)) {
+		ret = PTR_ERR(mmio);
 		goto free_rproc;
 	};