SBus Output missing for channel 9 ~ 16

[rmackay9]

As reported here on the Copter 4.5 forums, it seems that SBus output for channel 9 to 16 is not working in 4.5.0.

The testing setup was similar to that used for issue #26815 which is namely one CubeOrange's SBus output was connected to another CubeOrange's SBus input.

Autopilot 1 was setup so that the RC input from channel 6 was output on channels 5, 8, 9 and 16

Autopilot 2's RC input was connected to Autopilot 1's SBus output. With Autopilot 1 running 4.4.4, Autopilot2's RC input showed channel 5, 8, 9 and 16 correctly.

With Autopilot 1 running 4.6.0-dev, Autopilot 2's RC input showed channel 8 to 16 were not being output

[andyp1per]

Fixed by #26898