can: xilinx_can: xcan_probe(): check for error irq

For the possible failure of the platform_get_irq(), the returned irq
could be error number and will finally cause the failure of the
request_irq().

Consider that platform_get_irq() can now in certain cases return
-EPROBE_DEFER, and the consequences of letting request_irq()
effectively convert that into -EINVAL, even at probe time rather than
later on. So it might be better to check just now.

Fixes: b1201e4 ("can: xilinx CAN controller support")
Link: https://lore.kernel.org/all/20211224021324.1447494-1-jiasheng@iscas.ac.cn
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/xilinx_can.c

@@ -1761,7 +1761,12 @@ static int xcan_probe(struct platform_device *pdev)
 	spin_lock_init(&priv->tx_lock);
 
 	/* Get IRQ for the device */
-	ndev->irq = platform_get_irq(pdev, 0);
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		goto err_free;
+
+	ndev->irq = ret;
+
 	ndev->flags |= IFF_ECHO;	/* We support local echo */
 
 	platform_set_drvdata(pdev, ndev);