usb: musb: jz4740: fix error check of usb_get_phy()

The usb_get_phy() function returns either a valid pointer to phy or
ERR_PTR() error, check for NULL always fails and may lead to oops on
error path, fix this issue.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/jz4740.c

@@ -83,9 +83,9 @@ static int jz4740_musb_init(struct musb *musb)
 {
 	usb_phy_generic_register();
 	musb->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
-	if (!musb->xceiv) {
+	if (IS_ERR(musb->xceiv)) {
 		pr_err("HS UDC: no transceiver configured\n");
-		return -ENODEV;
+		return PTR_ERR(musb->xceiv);
 	}
 
 	/* Silicon does not implement ConfigData register.