Pull UBI/UBIFS updates from Richard Weinberger:
 "Minor fixes for UBI and UBIFS"

* tag 'upstream-4.2-rc1' of git://git.infradead.org/linux-ubifs:
  UBI: Remove unnecessary `\'
  UBI: Use static class and attribute groups
  UBI: add a helper function for updatting on-flash layout volumes
  UBI: Fastmap: Do not add vol if it already exists
  UBI: Init vol->reserved_pebs by assignment
  UBI: Fastmap: Rename variables to make them meaningful
  UBI: Fastmap: Remove unnecessary `\'
  UBI: Fastmap: Use max() to get the larger value
  ubifs: fix to check error code of register_shrinker
  UBI: block: Dynamically allocate minor numbers