Add group 0 & 1 options to ftdi_eeprom, and fix group1 eeprom offset for ft232h

Add group 0 & 1 options to ftdi_eeprom, and fix group1 eeprom offset for ft232h

This is a WIP patch for ftdi_eeprom that adds support for drive,
slew and schmitt settings for both ADBUS and ACBUS on the ft232h (currently
only group0_drive exists). I also changed the offset used for the group1
settings in ftdi.c: The eeprom (with stock configuration) of my um232h seems
to have the same memory map used in the 2232h and 4232h for these settings.

The factory defaults are:

group0_drive=8MA
group0_slew=false
group0_schmitt=false
group1_drive=8MA
group1_slew=false
group1_schmitt=false

Signed-off-by: Brian Gomes Bascoy (pera) <brian@recursive.fun>