[PATCH] Documentation for lock_key in struct hrtimer_base

Fixes an error message on make xmldocs.
Signed-off-by: Henrik Kretzschmar <henne@nachtwindheim.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/hrtimer.h

@@ -80,6 +80,7 @@ struct hrtimer_sleeper {
  * @get_softirq_time:	function to retrieve the current time from the softirq
  * @curr_timer:		the timer which is executing a callback right now
  * @softirq_time:	the time when running the hrtimer queue in the softirq
+ * @lock_key:		the lock_class_key for use with lockdep
  */
 struct hrtimer_base {
 	clockid_t		index;