can: m_can: m_can_class_free_dev(): introduce new function

This patch creates a common function that peripherials can call to free the
netdev device when failures occur.

Fixes: f524f829b7 ("can: m_can: Create a m_can platform framework")
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: http://lore.kernel.org/r/20200227183829.21854-2-dmurphy@ti.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/m_can/m_can.c

@@ -1812,6 +1812,12 @@ out:
 }
 EXPORT_SYMBOL_GPL(m_can_class_allocate_dev);
 
+void m_can_class_free_dev(struct net_device *net)
+{
+	free_candev(net);
+}
+EXPORT_SYMBOL_GPL(m_can_class_free_dev);
+
 int m_can_class_register(struct m_can_classdev *m_can_dev)
 {
 	int ret;

drivers/net/can/m_can/m_can.h

@@ -99,6 +99,7 @@ struct m_can_classdev {
 };
 
 struct m_can_classdev *m_can_class_allocate_dev(struct device *dev);
+void m_can_class_free_dev(struct net_device *net);
 int m_can_class_register(struct m_can_classdev *cdev);
 void m_can_class_unregister(struct m_can_classdev *cdev);
 int m_can_class_get_clocks(struct m_can_classdev *cdev);