visomat-data-downloader: increase the eeprom buffer size

visomat-data-downloader: increase the eeprom buffer size

Apparently the device can store up to 60 records per user, for 2 users,
and each record is 20 bytes.

Considering that the data has some header info like:

  M160...M260...

the buffer must be at least:

 (20 * 60 * 2) + 8 + 2  = 2410 bytes

Finally, the extra 2 bytes are the STX and ETX bytes.

Increase the buffer size to 4096 bytes to be safe.

Thanks-to: Cornelis Broeders <cornelis.broeders@web.de>