can: cc770: store echo skb before starting the transfer

On slow systems and high CAN bitrates, the error message
"can_put_echo_skb: BUG! echo_skb is occupied!" did show up because
can_put_echo_skb() was called after starting the transfer.
Signed-off-by: NWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/cc770/cc770.c

@@ -440,12 +440,14 @@ static netdev_tx_t cc770_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	for (i = 0; i < dlc; i++)
 		cc770_write_reg(priv, msgobj[mo].data[i], cf->data[i]);
 
+	/* Store echo skb before starting the transfer */
+	can_put_echo_skb(skb, dev, 0);
+
 	cc770_write_reg(priv, msgobj[mo].ctrl1,
 			RMTPND_RES | TXRQST_SET | CPUUPD_RES | NEWDAT_UNC);
 
 	stats->tx_bytes += dlc;
 
-	can_put_echo_skb(skb, dev, 0);
 
 	/*
 	 * HM: We had some cases of repeated IRQs so make sure the