can: c_can: add LED trigger support

Add support for canbus activity led indicators on c_can devices by
calling appropriate can_led functions.

These are only enabled when CONFIG_CAN_LEDS is Y, becomes no-op
otherwise.

Cc: Bhupesh Sharma <[e-mail]>
Cc: AnilKumar Ch <[e-mail]>
Cc: Wolfgang Grandegger <[e-mail]>
Cc: Marc Kleine-Budde <[e-mail]>
Signed-off-by: Fabio Baltieri <[e-mail]>
Signed-off-by: Marc Kleine-Budde <[e-mail]>

drivers/net/can/c_can/c_can.c

···
 #include <linux/can.h>
 #include <linux/can/dev.h>
 #include <linux/can/error.h>
+#include <linux/can/led.h>
 
 #include "c_can.h"
 
···
 	stats->rx_packets++;
 	stats->rx_bytes += frame->can_dlc;
 
+	can_led_event(dev, CAN_LED_EVENT_RX);
+
 	return 0;
 }
 
···
 					C_CAN_IFACE(MSGCTRL_REG, 0))
 					& IF_MCONT_DLC_MASK;
 			stats->tx_packets++;
+			can_led_event(dev, CAN_LED_EVENT_TX);
 			c_can_inval_msg_object(dev, 0, msg_obj_no);
 		} else {
 			break;
···
 
 	napi_enable(&priv->napi);
 
+	can_led_event(dev, CAN_LED_EVENT_OPEN);
+
 	/* start the c_can controller */
 	c_can_start(dev);
 
···
 
 	c_can_reset_ram(priv, false);
 	c_can_pm_runtime_put_sync(priv);
+
+	can_led_event(dev, CAN_LED_EVENT_STOP);
 
 	return 0;
 }
···
 	err = register_candev(dev);
 	if (err)
 		c_can_pm_runtime_disable(priv);
+	else
+		devm_can_led_init(dev);
 
 	return err;
 }