AP_Periph: allow airspeed without I2C #38262

Job	Run time
build (stm32f7, chibios, 10)	4m 10s
build (stm32h7, chibios, 10)	3m 30s
build (fmuv2-plane, chibios, 10)	1m 50s
build (periph-build, chibios, 10)	3m 45s
build (iofirmware, chibios, 10)	1m 25s
build (CubeOrange-bootloader, chibios, 10)	54s
build (fmuv3-bootloader, chibios, 10)	48s
build (revo-bootloader, chibios, 10)	1m 6s
build (stm32h7-debug, chibios, 10)	2m 5s
build (fmuv3, chibios, 10)	4m 58s
build (revo-mini, chibios, 10)	3m 59s
build (MatekF405-Wing, chibios, 10)	4m 8s
build (CubeOrange-ODID, chibios, 10)	2m 34s
build (CubeRedPrimary-bootloader, chibios, 10)	48s
build (configure-all, chibios, 10)	9m 31s
build (build-options-defaults-test, chibios, 10)	7m 37s
build (signing, chibios, 10)	2m 32s
build (CubeOrange-PPP, chibios, 10)	2m 22s
build (SOHW, chibios, 10)	3m 23s
build (Pixhawk6X-PPPGW, chibios, 10)	1m 10s
	1h 2m 35s

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