mm: docs: fix parameter names mismatch

There are several places where parameter descriptions do no match the
actual code.  Fix it.

Link: http://lkml.kernel.org/r/1516700871-22279-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swap.c

@@ -913,11 +913,11 @@ EXPORT_SYMBOL(__pagevec_lru_add);
  * @pvec:	Where the resulting entries are placed
  * @mapping:	The address_space to search
  * @start:	The starting entry index
- * @nr_entries:	The maximum number of entries
+ * @nr_pages:	The maximum number of pages
  * @indices:	The cache indices corresponding to the entries in @pvec
  *
  * pagevec_lookup_entries() will search for and return a group of up
- * to @nr_entries pages and shadow entries in the mapping.  All
+ * to @nr_pages pages and shadow entries in the mapping.  All
  * entries are placed in @pvec.  pagevec_lookup_entries() takes a
  * reference against actual pages in @pvec.
  *