can: m_can: add .ndo_change_mtu function

Use common can_change_mtu function.

Signed-off-by: Dong Aisheng <b29396@freescale.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 10d571e..e61886b 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -992,6 +992,7 @@
 	.ndo_open = m_can_open,
 	.ndo_stop = m_can_close,
 	.ndo_start_xmit = m_can_start_xmit,
+	.ndo_change_mtu = can_change_mtu,
 };
 
 static int register_m_can_dev(struct net_device *dev)