can: unify identifiers to ensure unique include processing

Armin pointed me to the fact that the identifier which is used to ensure the
unique include processing in lunux/include/uapi/linux/can.h is CAN_H.
This clashed with his own source as includes from libraries and APIs should
use an underscore '_' at the identifier start.

This patch fixes the protection identifiers in all CAN relavant includes.

Reported-by: Armin Burchardt <armin@uni-bremen.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
diff --git a/include/linux/can/led.h b/include/linux/can/led.h
index 9c1167ba..e0475c5 100644
--- a/include/linux/can/led.h
+++ b/include/linux/can/led.h
@@ -6,8 +6,8 @@
  * published by the Free Software Foundation.
  */
 
-#ifndef CAN_LED_H
-#define CAN_LED_H
+#ifndef _CAN_LED_H
+#define _CAN_LED_H
 
 #include <linux/if.h>
 #include <linux/leds.h>
@@ -48,4 +48,4 @@
 
 #endif
 
-#endif
+#endif /* !_CAN_LED_H */