AP_Periph: Change division to multiplication #45189

Job	Run time
build (stm32f7, chibios, 10)	4m 21s
build (stm32h7, chibios, 10)	4m 56s
build (fmuv2-plane, chibios, 10)	2m 6s
build (periph-build, chibios, 10)	3m 59s
build (iofirmware, chibios, 10)	1m 33s
build (CubeOrange-bootloader, chibios, 10)	53s
build (fmuv3-bootloader, chibios, 10)	50s
build (revo-bootloader, chibios, 10)	1m 5s
build (stm32h7-debug, chibios, 10)	3m 23s
build (fmuv3, chibios, 10)	9m 8s
build (revo-mini, chibios, 10)	4m 37s
build (MatekF405-Wing, chibios, 10)	4m 48s
build (CubeOrange-ODID, chibios, 10)	3m 59s
build (CubeRedPrimary-bootloader, chibios, 10)	49s
build (configure-all, chibios, 10)	11m 37s
build (build-options-defaults-test, chibios, 10)	10m 2s
build (signing, chibios, 10)	3m 33s
build (CubeOrange-PPP, chibios, 10)	2m 51s
build (CubeRed-EKF2, chibios, 10)	3m 13s
build (SOHW, chibios, 10)	4m 55s
build (Pixhawk6X-PPPGW, chibios, 10)	1m 11s
build (new-check, chibios, 10)	7m 39s
	1h 31m 28s

Provide feedback