mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

Source kernel commit 09cbfeaf1a5a67bfb3201e0c83c810cecb2efa5a

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

[....]

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>
Signed-off-by: Dave Chinner <david@fromorbit.com>