GCS_Common: better handle negative intervals #46185

Job	Run time
build (stm32f7, chibios, 10)	13m 39s
build (stm32h7, chibios, 10)	12m 25s
build (fmuv2-plane, chibios, 10)	1m 51s
build (periph-build, chibios, 10)	13m 51s
build (iofirmware, chibios, 10)	2m 54s
build (CubeOrange-bootloader, chibios, 10)	49s
build (fmuv3-bootloader, chibios, 10)	1m 7s
build (revo-bootloader, chibios, 10)	1m 26s
build (stm32h7-debug, chibios, 10)	7m 5s
build (fmuv3, chibios, 10)	5m 51s
build (revo-mini, chibios, 10)	10m 35s
build (MatekF405-Wing, chibios, 10)	11m 17s
build (CubeOrange-ODID, chibios, 10)	2m 59s
build (CubeRedPrimary-bootloader, chibios, 10)	57s
build (configure-all, chibios, 10)	11m 11s
build (build-options-defaults-test, chibios, 10)	7m 29s
build (signing, chibios, 10)	10m 3s
build (CubeOrange-PPP, chibios, 10)	2m 13s
build (CubeRed-EKF2, chibios, 10)	2m 26s
build (SOHW, chibios, 10)	10m 44s
build (Pixhawk6X-PPPGW, chibios, 10)	3m 0s
build (new-check, chibios, 10)	13m 52s
	2h 27m 44s

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