AP_Periph arm timeout bug #451

Job	Run time
build (stm32f7, chibios, 10)	6m 9s
build (stm32h7, chibios, 10)	3m 51s
build (fmuv2-plane, chibios, 10)	2m 45s
build (periph-build, chibios, 10)	7m 4s
build (iofirmware, chibios, 10)	1m 15s
build (CubeOrange-bootloader, chibios, 10)	1m 26s
build (revo-bootloader, chibios, 10)	1m 47s
build (stm32h7-debug, chibios, 10)	3m 23s
build (fmuv3, chibios, 10)	6m 18s
build (revo-mini, chibios, 10)	6m 23s
build (MatekF405-Wing, chibios, 10)	5m 27s
build (CubeOrange-ODID, chibios, 10)	3m 10s
build (configure-all, chibios, 10)	8m 9s
build (build-options-defaults-test, chibios, 10)	9m 10s
build (signing, chibios, 10)	3m 56s
	1h 10m 13s

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