usb: host: ehci-s5p: fix PHY error handling

PHY layer no longer returns NULL. We must
switch from IS_ERR_OR_NULL() to IS_ERR().

Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/host/ehci-s5p.c b/drivers/usb/host/ehci-s5p.c
index 20ebf6a..867a923 100644
--- a/drivers/usb/host/ehci-s5p.c
+++ b/drivers/usb/host/ehci-s5p.c
@@ -139,7 +139,7 @@
 		return -ENOMEM;
 
 	phy = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
-	if (IS_ERR_OR_NULL(phy)) {
+	if (IS_ERR(phy)) {
 		/* Fallback to pdata */
 		if (!pdata) {
 			dev_warn(&pdev->dev, "no platform data or transceiver defined\n");