can: mcp251x: add missing IRQF_ONESHOT to request_threaded_irq

Since commit:

    1c6c695 genirq: Reject bogus threaded irq requests

threaded irqs must provide a primary handler or set the IRQF_ONESHOT flag.
Since the mcp251x driver doesn't make use of a primary handler set the
IRQF_ONESHOT flag.

Cc: linux-stable <stable@vger.kernel.org> # >= v3.5
Reported-by: Mylene Josserand <Mylene.Josserand@navocap.com>
Tested-by: Mylene Josserand <Mylene.Josserand@navocap.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/mcp251x.c

@@ -929,6 +929,7 @@ static int mcp251x_open(struct net_device *net)
 	struct mcp251x_priv *priv = netdev_priv(net);
 	struct spi_device *spi = priv->spi;
 	struct mcp251x_platform_data *pdata = spi->dev.platform_data;
+	unsigned long flags;
 	int ret;
 
 	ret = open_candev(net);
@@ -945,9 +946,14 @@ static int mcp251x_open(struct net_device *net)
 	priv->tx_skb = NULL;
 	priv->tx_len = 0;
 
+	flags = IRQF_ONESHOT;
+	if (pdata->irq_flags)
+		flags |= pdata->irq_flags;
+	else
+		flags |= IRQF_TRIGGER_FALLING;
+
 	ret = request_threaded_irq(spi->irq, NULL, mcp251x_can_ist,
-		  pdata->irq_flags ? pdata->irq_flags : IRQF_TRIGGER_FALLING,
-		  DEVICE_NAME, priv);
+				   flags, DEVICE_NAME, priv);
 	if (ret) {
 		dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq);
 		if (pdata->transceiver_enable)