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outdated comments.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/gup.c b/mm/gup.c
index 7f1c4fb..fb87aea 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1107,7 +1107,7 @@
  * @addr: user address
  *
  * Returns struct page pointer of user page pinned for dump,
- * to be freed afterwards by page_cache_release() or put_page().
+ * to be freed afterwards by put_page().
  *
  * Returns NULL on any kind of failure - a hole must then be inserted into
  * the corefile, to preserve alignment with its headers; and also returns