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outdated comments.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/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index c121747..eeeade7 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -119,7 +119,7 @@
  *
  *
  * one block each for bitmap and buddy information.  So for each group we
- * take up 2 blocks. A page can contain blocks_per_page (PAGE_CACHE_SIZE /
+ * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
  * blocksize) blocks.  So it can have information regarding groups_per_page
  * which is blocks_per_page/2
  *
@@ -807,7 +807,7 @@
  *
  * one block each for bitmap and buddy information.
  * So for each group we take up 2 blocks. A page can
- * contain blocks_per_page (PAGE_CACHE_SIZE / blocksize)  blocks.
+ * contain blocks_per_page (PAGE_SIZE / blocksize)  blocks.
  * So it can have information regarding groups_per_page which
  * is blocks_per_page/2
  *