typo fixes: occuring -> occurring

Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 1535af3..ee8c6dfd 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1064,7 +1064,7 @@
 }
 
 /*
- * Frequency meter - How fast is some event occuring?
+ * Frequency meter - How fast is some event occurring?
  *
  * These routines manage a digitally filtered, constant time based,
  * event frequency meter.  There are four routines: