usb: dwc3: core: cope with NULL pdata

if pdata is a NULL pointer we could cause a
kernel oops when probing the driver. Make sure
to cope with systems which won't pass pdata
to the driver.
Tested-by: NPaul Zimmerman <paulz@synopsys.com>
Reported-by: NPaul Zimmerman <paulz@synopsys.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/core.c

@@ -393,7 +393,7 @@ static int dwc3_probe(struct platform_device *pdev)
 
 		dwc->needs_fifo_resize = of_property_read_bool(node, "tx-fifo-resize");
 		dwc->dr_mode = of_usb_get_dr_mode(node);
-	} else {
+	} else if (pdata) {
 		dwc->maximum_speed = pdata->maximum_speed;
 
 		dwc->usb2_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
@@ -401,6 +401,9 @@ static int dwc3_probe(struct platform_device *pdev)
 
 		dwc->needs_fifo_resize = pdata->tx_fifo_resize;
 		dwc->dr_mode = pdata->dr_mode;
+	} else {
+		dwc->usb2_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
+		dwc->usb3_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB3);
 	}
 
 	/* default to superspeed if no maximum_speed passed */