usb: gadget: mv_udc: fix the value of tranceiver

usally we will use udc->tranceiver == NULL or
udc->tranceiver != NULL.
So when failed to get the udc->tranceiver by usb_get_phy(), we
directly set udc->tranceiver to be NULL.
Then the source code will not need macro IS_ERR_OR_NULL() for
udc->tranceiver judgement. It can reduce the line size and make
the judgement simple.
Signed-off-by: Chao Xie <chao.xie@marvell.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/mv_udc_core.c

@@ -1394,7 +1394,7 @@ static int mv_udc_start(struct usb_gadget *gadget,
 
 	spin_unlock_irqrestore(&udc->lock, flags);
 
-	if (!IS_ERR_OR_NULL(udc->transceiver)) {
+	if (udc->transceiver) {
 		retval = otg_set_peripheral(udc->transceiver->otg,
 					&udc->gadget);
 		if (retval) {
@@ -2174,9 +2174,14 @@ static int mv_udc_probe(struct platform_device *pdev)
 	udc->dev = pdev;
 
 #ifdef CONFIG_USB_OTG_UTILS
-	if (pdata->mode == MV_USB_MODE_OTG)
+	if (pdata->mode == MV_USB_MODE_OTG) {
 		udc->transceiver = devm_usb_get_phy(&pdev->dev,
 					USB_PHY_TYPE_USB2);
+		if (IS_ERR_OR_NULL(udc->transceiver)) {
+			udc->transceiver = NULL;
+			return -ENODEV;
+		}
+	}
 #endif
 
 	udc->clknum = pdata->clknum;
@@ -2319,7 +2324,7 @@ static int mv_udc_probe(struct platform_device *pdev)
 	eps_init(udc);
 
 	/* VBUS detect: we can disable/enable clock on demand.*/
-	if (!IS_ERR_OR_NULL(udc->transceiver))
+	if (udc->transceiver)
 		udc->clock_gating = 1;
 	else if (pdata->vbus) {
 		udc->clock_gating = 1;
@@ -2386,7 +2391,7 @@ static int mv_udc_suspend(struct device *dev)
 	udc = dev_get_drvdata(dev);
 
 	/* if OTG is enabled, the following will be done in OTG driver*/
-	if (!IS_ERR_OR_NULL(udc->transceiver))
+	if (udc->transceiver)
 		return 0;
 
 	if (udc->pdata->vbus && udc->pdata->vbus->poll)
@@ -2421,7 +2426,7 @@ static int mv_udc_resume(struct device *dev)
 	udc = dev_get_drvdata(dev);
 
 	/* if OTG is enabled, the following will be done in OTG driver*/
-	if (!IS_ERR_OR_NULL(udc->transceiver))
+	if (udc->transceiver)
 		return 0;
 
 	if (!udc->clock_gating) {