altos: Fix config upgrade from 1.24 to 1.25

Alignment of pyro field changed due to increased size of fields which
shifted the whole struct by two bytes, leading to mis-updating the struct.
Fix that by creating a mirror of the ao_config type for version 1.24 and
then using that to fetch the old data.

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