usb: mtu3: fix error return code in ssusb_gadget_init()

When failing to get IRQ number, platform_get_irq() may return
-EPROBE_DEFER, but we ignore it and always return -ENODEV,
so fix it.
Signed-off-by: NChunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/mtu3/mtu3_core.c

@@ -774,9 +774,9 @@ int ssusb_gadget_init(struct ssusb_mtk *ssusb)
 		return -ENOMEM;
 
 	mtu->irq = platform_get_irq(pdev, 0);
-	if (mtu->irq <= 0) {
+	if (mtu->irq < 0) {
 		dev_err(dev, "fail to get irq number\n");
-		return -ENODEV;
+		return mtu->irq;
 	}
 	dev_info(dev, "irq %d\n", mtu->irq);