- it does not make sense to specify '-i bytes-per-inode' in
  combination with '-N number-of-inodes'. Thus only the number
  of inodes is relevant as it's the result of the equation
  inodes = size / ratio. It had no bad impact to specify
  both -i and -N when creating the filesystem because mkfs.extX
  takes the value of -N with the highest priority. Thus this
  fix is just a cleanup of the mkfs.extX call