can: m_can: Release irq on error in m_can_open

It appears that the irq requested in m_can_open() may be leaked
if an error subsequently occurs: if m_can_start() fails.

Address this by calling free_irq in the unwind path for
such cases.

Flagged by Smatch.
Compile tested only.

Fixes: eaacfea ("can: m_can: Call the RAM init directly from m_can_chip_config")
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/all/20240805-mcan-irq-v2-1-7154c0484819@kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Author: horms

drivers/net/can/m_can/m_can.c

@@ -2052,7 +2052,7 @@ static int m_can_open(struct net_device *dev)
 	/* start the m_can controller */
 	err = m_can_start(dev);
 	if (err)
-		goto exit_irq_fail;
+		goto exit_start_fail;
 
 	if (!cdev->is_peripheral)
 		napi_enable(&cdev->napi);
@@ -2061,6 +2061,9 @@ static int m_can_open(struct net_device *dev)
 
 	return 0;
 
+exit_start_fail:
+	if (cdev->is_peripheral || dev->irq)
+		free_irq(dev->irq, dev);
 exit_irq_fail:
 	if (cdev->is_peripheral)
 		destroy_workqueue(cdev->tx_wq);