hwdef: ARKV6x: fix RC input

[dakejahl]

This reverts 9f5e837. I believe when I tested that PR I didn't run waf configure and therefore the hwdef changes never got applied. So I thought I fixed something that was never broken to begin with 🤦

I tested this on an ARK Jetson Carrier with an ARKV6X

requirements for SBUS
SERIAL8_PROTOCOL = 23 (RCIN)
RC_PROTOCOL = 1 (all)

@tridge I think this should make more sense, let me know if there's anything I missed!

We can close #27736

[peterbarker]

Added WikiNeeded on a hunch.

[dakejahl]

Added WikiNeeded on a hunch.

This wiki here? https://github.com/ArduPilot/ardupilot_wiki

What kind of information typically goes in the wiki? At the very least it would be good to document which serial ports correspond to which SERIAL* parameters. And any other basic getting started information specific to the hardware would be good to document. PX4 docs have some vendor specific documentation, should we add the same for Ardupilot?

eg
ARKV6X
https://docs.px4.io/main/en/flight_controller/arkv6x.html
ARK Flow
https://docs.px4.io/main/en/dronecan/ark_flow.html