Ensure valid flash range for rp2040-dev

The current flash range for the rp2040 was quickly thrown together and has not been verified to work. This code from an earlier version worked at the time. Maybe just use these values.

https://github.com/holsatus/holsatus-flight/blob/45d3e6ff308e36055671925fc684e56a04d9a967/src/config/mod.rs#L148C1-L153C1
