usb: dwc3: fix PHY error handling

PHY layer no longer returns NULL. It will
return -ENXIO when PHY layer isn't enabled
and we can use that to bail out instead of
request a probe deferral.
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/core.c

@@ -434,12 +434,32 @@ static int dwc3_probe(struct platform_device *pdev)
 		dwc->usb3_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB3);
 	}
 
-	if (IS_ERR_OR_NULL(dwc->usb2_phy)) {
+	if (IS_ERR(dwc->usb2_phy)) {
+		ret = PTR_ERR(dwc->usb2_phy);
+
+		/*
+		 * if -ENXIO is returned, it means PHY layer wasn't
+		 * enabled, so it makes no sense to return -EPROBE_DEFER
+		 * in that case, since no PHY driver will ever probe.
+		 */
+		if (ret == -ENXIO)
+			return ret;
+
 		dev_err(dev, "no usb2 phy configured\n");
 		return -EPROBE_DEFER;
 	}
 
-	if (IS_ERR_OR_NULL(dwc->usb3_phy)) {
+	if (IS_ERR(dwc->usb3_phy)) {
+		ret = PTR_ERR(dwc->usb2_phy);
+
+		/*
+		 * if -ENXIO is returned, it means PHY layer wasn't
+		 * enabled, so it makes no sense to return -EPROBE_DEFER
+		 * in that case, since no PHY driver will ever probe.
+		 */
+		if (ret == -ENXIO)
+			return ret;
+
 		dev_err(dev, "no usb3 phy configured\n");
 		return -EPROBE_DEFER;
 	}