EKF2 remove FW_ARSP_MODE check

[dagar]

This is a FW controller configuration parameter, and we already have a mechanism to disable airspeed fusion in EKF2, or to disable the airspeed sensor entirely.

As an example of why this isn't quite right, here are the parameters for a regular multicopter.

[LorenzMeier]

This looks like it will potentially break existing setups - what happens if someone who has configured this upgrades?

[dagar]

It would have to be someone that has an active working airspeed sensor, set the FW controllers to airspeed disabled mode, didn't set the circuit breaker, and then set the EKF2 airspeed fusion threshold. Then it's a question of how the EKF would handle these actual airspeed readings.

EKF2_ARSP_THR - airspeed fusion threshold (defaults to 0 for off)
CBRK_AIRSPD_CHK - disable airspeed sensor check (also skips differential pressure startup in init)
FW_ARSP_MODE - tells the FW controllers not to use the airspeed sensor

It seems pretty clear to me that the setting for the FW controllers shouldn't be used within the estimator configuration, and the estimator already has a mechanism for ignoring airspeed. It's also possible that someone might want to use airspeed fusion in the estimator, but ignore airspeed in the controllers.