AC_AttitudeControl: Fix yaw limit calculations #1140

Job	Run time
build (stm32f7, chibios, 10)	19m 20s
build (stm32h7, chibios, 10)	21m 49s
build (fmuv2-plane, chibios, 10)	7m 3s
build (periph-build, chibios, 10)	26m 46s
build (iofirmware, chibios, 10)	3m 59s
build (CubeOrange-bootloader, chibios, 10)	1m 59s
build (fmuv3-bootloader, chibios, 10)	1m 21s
build (revo-bootloader, chibios, 10)	1m 34s
build (stm32h7-debug, chibios, 10)	10m 4s
build (fmuv3, chibios, 10)	16m 34s
build (revo-mini, chibios, 10)	19m 19s
build (MatekF405-Wing, chibios, 10)	18m 0s
build (CubeOrange-ODID, chibios, 10)	10m 11s
build (CubeRedPrimary-bootloader, chibios, 10)	1m 33s
build (configure-all, chibios, 10)	12m 32s
build (build-options-defaults-test, chibios, 10)	25m 46s
build (signing, chibios, 10)	12m 39s
	3h 30m 29s

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