Add MAVLink receiver support, RADIO_RC_CHANNELS, no III #36539

Job	Run time
build (stm32f7, chibios, 10)	10m 8s
build (stm32h7, chibios, 10)	7m 57s
build (fmuv2-plane, chibios, 10)	3m 38s
build (periph-build, chibios, 10)	5m 51s
build (iofirmware, chibios, 10)	1m 46s
build (CubeOrange-bootloader, chibios, 10)	50s
build (fmuv3-bootloader, chibios, 10)	53s
build (revo-bootloader, chibios, 10)	57s
build (stm32h7-debug, chibios, 10)	4m 31s
build (fmuv3, chibios, 10)	10m 46s
build (revo-mini, chibios, 10)	8m 8s
build (MatekF405-Wing, chibios, 10)	8m 33s
build (CubeOrange-ODID, chibios, 10)	5m 51s
build (CubeRedPrimary-bootloader, chibios, 10)	50s
build (configure-all, chibios, 10)	9m 0s
build (build-options-defaults-test, chibios, 10)	18m 34s
build (signing, chibios, 10)	5m 19s
build (CubeOrange-PPP, chibios, 10)	4m 26s
build (CubeOrange-SOHW, chibios, 10)	5m 11s
build (Pixhawk6X-PPPGW, chibios, 10)	2m 2s
	1h 55m 11s

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