altosuilib: Get the Eeprom download progress bar working again

The eeprom download code wasn't computing the start of each state
transition correctly, so the progress bar was snapping to the end of
the chunk for each state.

Invalid state values would snap the bar to the right side.

Landed state wasn't ever seen, so the bar would not ever fill.

Signed-off-by: Keith Packard <keithp@keithp.com>