suggested in review by Heikki.


innobase/include/data0type.h:
  Improve comment of dtype_struct.
innobase/include/data0type.ic:
  Rename innobase_get_mb_cset() to innobase_get_cset_width().
  dtype_get_fixed_size(): Add an extra integrity check for
  type->prtype, type->mbminlen and type->mbmaxlen.
sql/ha_innodb.cc:
  Rename innobase_get_mb_cset() to innobase_get_cset_width()