Pull UBI/UBIFS updates from Richard Weinberger:
 "This contains cleanups and a maintainer update for UBI and UBIFS"

* tag 'upstream-4.6-rc1' of git://git.infradead.org/linux-ubifs:
  ubifs: Remove unused header
  MAINTAINERS: Update UBIFS entry
  mtd: ubi: Add logging functions ubi_msg, ubi_warn and ubi_err
  ubifs: Add logging functions for ubifs_msg, ubifs_err and ubifs_warn