mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage

Mostly direct substitution with occasional adjustment or removing
outdated comments.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swap.c b/mm/swap.c
index ea641e2..a0bc206 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -698,7 +698,7 @@
 }
 
 /**
- * release_pages - batched page_cache_release()
+ * release_pages - batched put_page()
  * @pages: array of pages to release
  * @nr: number of pages
  * @cold: whether the pages are cache cold