si-test should be careful about overwriting readout params in cameras with non-volatile storage

[garlick]

The behavior of si-test is to read "readout" info (including ADC offsets) from the setfile and write it to the camera unconditionally as part of initialization.

That does not appear to be necessary with some cameras. The model 806 camera for example retains readout parameters across a power cycle. Furthermore, since those parameters (especially ADC offsets) are unique per camera and might only be available in the camera's non-volatile memory, it would be a shame to overwrite them if a setfile from another camera is specified.

This could be handled a few different ways. One would be to read the camera's model and serial and refuse to use a setfile from a different camera. Another would be to "whitelist" camera models that require the readout param overwrite, or "blacklist" models that do not.