mm/workingset.c: fix some doc warnings

Fix following warnings caused by mismatch bewteen function parameters and
comments.

mm/workingset.c:228: warning: Function parameter or member 'lruvec' not described in 'workingset_age_nonresident'
mm/workingset.c:228: warning: Excess function parameter 'memcg' description in 'workingset_age_nonresident'
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/1600485913-11192-1-git-send-email-tanxiaofei@huawei.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/workingset.c

@@ -216,7 +216,7 @@ static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat,
 
 /**
  * workingset_age_nonresident - age non-resident entries as LRU ages
- * @memcg: the lruvec that was aged
+ * @lruvec: the lruvec that was aged
  * @nr_pages: the number of pages to count
  *
  * As in-memory pages are aged, non-resident pages need to be aged as