remove AP_MotorsMatrixTS

[kd0aij]

there were only two frame types unique to copter tailsitters, and the simplified implementation of function AP_MotorsMatrixTS::output_armed_stabilizing appears to be unnecessary

@rmackay9 This just absorbs support for the 2 quad-no-yaw-torque frame types used by copter tailsitters into AP_MotorsMatrix, and should have no functional impact on any other frame type.

[rmackay9]

Hi, do we need any changes for the parameter descriptions or is that all done on the Plane side?

[kd0aij]

I should have been saying frame_type above, instead of frame_class.
The two frame_types created for copter tailsitters are in the description for the quadplane parameter, but not in the frame_type description for Copter. Perhaps leaving them out in Copter would address Pete's concern above?
At present, the quadplane description is missing frame_type=18 and Copter is missing frame_type=16 and 17

[rmackay9]

@kd0aij, Probably both leaving it out of the parameter description and making it unavailable for the Copter firmware makes sense.

[kd0aij]

Would you prefer a pre-arm check or the #if approach in MotorsMatrix?

[rmackay9]

@kd0aij, I think if some #ifs are added then an existing pre-arm check will catch that the motor driver hasn't been initialised successfully.

[kd0aij]

Restricted frame_types 17,18 to ArduPlane builds