Merge changes from topic 'update_dering' into nextgenv2

* changes:
  Reformatting the deringing code
  Introducing OD_DERING_SIZE_LOG2 constant (3)
  Renaming deringing blockwise write-back functions to make code clearer
  Deringing refactoring: replace last_sbc with simpler dering_left flag
  Getting rid of the od_dering_in type