rc channel wasn't completely protected by #define guards #34901

Job	Run time
build (base)	6m 29s
build (clang)	8m 7s
autotest (sitltest-rover)	16m 43s
autotest (sitltest-sailboat)	2m 43s
autotest (sitltest-balancebot)	7m 52s
	41m 54s

Provide feedback