mm/swap.c: remove @cold parameter description for release_pages()

The 'cold' parameter was removed from release_pages function by commit
c6f92f9fbe7d ("mm: remove cold parameter for release_pages").

Update the description to match the code.

Link: http://lkml.kernel.org/r/1519585191-10180-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swap.c

@@ -707,7 +707,6 @@ void lru_add_drain_all(void)
  * release_pages - batched put_page()
  * @pages: array of pages to release
  * @nr: number of pages
- * @cold: whether the pages are cache cold
  *
  * Decrement the reference count on all the pages in @pages.  If it
  * fell to zero, remove the page from the LRU and free it.