v1.12.3: EKF2 do not work when SYS_HAS_BARO = 0

[aet2230]

Tried v1.12.3. On our application we use VIO only, and do not use magnetometer and barometer.
Tried do disable barometer and magnetometer chacks via SYS_HAS_* parameters (to avoid unwanted checks or other issues if unused HW is faulty)
After setting SYS_HAS_MAG = 0, works ok.
When SYS_HAS_BARO = 0, EKF2 does not start (or does not initialize). With SYS_HAS_BARO = 1, works OK, even if not used.

[dagar]

Currently baro data is required to initialize ekf2.

Previously I started refactoring things to only require the data for the specific height mode, but that's stalled. PX4/PX4-ECL#996

If you're able to help test and review we could resurrect the effort.

[lukegluke]

Temporary you could use this workaround for example that use gps height on initialization step if it fits you:
PX4/PX4-ECL#876 (comment)

[bresch]

This works now