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outdated comments.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/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index cc0fc71..7ca44fb 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -129,7 +129,7 @@
  *
  * These happen to all be powers of 2, which is not strictly
  * necessary but helps enforce the real limitation, which is
- * that they should be multiples of PAGE_CACHE_SIZE.
+ * that they should be multiples of PAGE_SIZE.
  *
  * For UDP transports, a block plus NFS,RPC, and UDP headers
  * has to fit into the IP datagram limit of 64K.  The largest