mm: fix kernel-doc warnings

Fix kernel-doc warnings such as

  Warning(../mm/page_cgroup.c:432): No description found for parameter 'id'
  Warning(../mm/page_cgroup.c:432): Excess function parameter 'mem' description in 'swap_cgroup_record'

Signed-off-by: Wanpeng Li <liwp@linux.vnet.ibm.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 1ccbd71..eb750f8 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -392,7 +392,7 @@
 
 /**
  * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
- * @end: swap entry to be cmpxchged
+ * @ent: swap entry to be cmpxchged
  * @old: old id
  * @new: new id
  *
@@ -422,7 +422,7 @@
 /**
  * swap_cgroup_record - record mem_cgroup for this swp_entry.
  * @ent: swap entry to be recorded into
- * @mem: mem_cgroup to be recorded
+ * @id: mem_cgroup to be recorded
  *
  * Returns old value at success, 0 at failure.
  * (Of course, old value can be 0.)