can: can327: fix a broken link to Documentation

Since commit 482a4360 ("docs: networking: convert netdevices.txt to
ReST"), Documentation/networking/netdevices.txt has been replaced by
Documentation/networking/netdevices.rst.

Update the comment accordingly to avoid a 'make htmldocs' warning.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/all/6a54aff884ea4f84b661527d75aabd6632140715.1659249135.git.christophe.jaillet@wanadoo.fr
Fixes: 43da2f07 ("can: can327: CAN/ldisc driver for ELM327 based OBD-II adapters")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/can327.c

@@ -827,7 +827,7 @@ static netdev_tx_t can327_netdev_start_xmit(struct sk_buff *skb,
 	netif_stop_queue(dev);
 
 	/* BHs are already disabled, so no spin_lock_bh().
-	 * See Documentation/networking/netdevices.txt
+	 * See Documentation/networking/netdevices.rst
 	 */
 	spin_lock(&elm->lock);
 	can327_send_frame(elm, frame);