AP_Airspeed: Add support for new message #39744

Job	Run time
build (base)	6m 43s
build (clang)	7m 38s
build-gcc-heli	7m 16s
autotest-heli (sitltest-heli)	13m 52s
autotest (sitltest-copter-tests1a)	12m 0s
autotest (sitltest-copter-tests1b)	13m 36s
autotest (sitltest-copter-tests1c)	15m 45s
autotest (sitltest-copter-tests1d)	13m 15s
autotest (sitltest-copter-tests1e)	13m 31s
autotest (sitltest-copter-tests2a)	13m 47s
autotest (sitltest-copter-tests2b)	34m 9s
	2h 31m 32s

Provide feedback