Update mkvcomblob script to match VCOM EEPROM format v1
pldata.mkvcomblob: fix typo + test function + board_type

* fix typo with adc_scale_2
* use StringEntry for the board type as it's a string
* update MD5 sum of the new sample data in test function
  (now it passes)
pldata.mkvcomblob: tidy-up long lines and whitespace
pldata.mkvcomblob: fix length of board_type entry
ChangeLog v007 -> v008