Merge branch 'upstream' of git://git.infradead.org/~dedekind/ubi-2.6

Merge branch 'upstream' of git://git.infradead.org/~dedekind/ubi-2.6

* 'upstream' of git://git.infradead.org/~dedekind/ubi-2.6: (28 commits)
  UBI: fix compile warning
  UBI: fix error handling in erase worker
  UBI: fix comments
  UBI: remove unneeded error checks
  UBI: cleanup usage of try_module_get
  UBI: fix overflow bug
  UBI: bugfix in max_sqnum calculation
  UBI: bugfix in sqnum calculation
  UBI: fix signed-unsigned multiplication
  UBI: fix bug in atomic_leb_change()
  UBI: fix message
  UBI: fix debugging stuff
  UBI: bugfix in error path
  UBI: use is_power_of_2()
  UBI: fix freeing ubi->vtbl while unloading
  UBI: fix MAINTAINERS
  UBI: bugfix in ubi_leb_change()
  UBI: kill homegrown endian macros
  UBI: cleanup ioctl handling
  UBI: error path bugfix
  ...