soc: ti: omap-prm: fix return value check in omap_prm_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().

Fixes: 3e99cb21 ("soc: ti: add initial PRM driver with reset control support")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

drivers/soc/ti/omap_prm.c

@@ -375,8 +375,8 @@ static int omap_prm_probe(struct platform_device *pdev)
 	prm->data = data;
 
 	prm->base = devm_ioremap_resource(&pdev->dev, res);
-	if (!prm->base)
-		return -ENOMEM;
+	if (IS_ERR(prm->base))
+		return PTR_ERR(prm->base);
 
 	return omap_prm_reset_init(pdev, prm);
 }