Merge tag 'md/4.0-rc7-fix' of git://neil.brown.name/md

Pull md fixes from Neil Brown:
 "Two regression fixes for md, one fairly recent and minor (diskstats
  has confusing data) and one older and more serious - RAID0 with
  non-power-of-2 chunksize corrupts data.

  I guess (almost) no-one uses non-power-of-2 chunks.

  Summary:

   - Revert recent change which broke IO accounting.

   - Fix bug with RAID0 arrays with non-power-of-2 chunk size"

* tag 'md/4.0-rc7-fix' of git://neil.brown.name/md:
  md/raid0: fix bug with chunksize not a power of 2.
  md: fix md io stats accounting broken