time: fix typo in comments

Fix typo in comments.

BTW: I have to fix coding style in arch/ia64/kernel/time.c also, otherwise
checkpatch.pl will be complaining.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 1d327f6..3d1e3e1 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -133,7 +133,7 @@
 }
 
 /*
- * Called after a notify add to make devices availble which were
+ * Called after a notify add to make devices available which were
  * released from the notifier call.
  */
 static void clockevents_notify_released(void)