AP_Param: add comments around G2 parameter conversion #3100

Job	Run time
build (stm32f7, chibios, 10)	13m 32s
build (stm32h7, chibios, 10)	12m 2s
build (fmuv2-plane, chibios, 10)	5m 26s
build (periph-build, chibios, 10)	11m 41s
build (iofirmware, chibios, 10)	2m 6s
build (CubeOrange-bootloader, chibios, 10)	1m 0s
build (fmuv3-bootloader, chibios, 10)	51s
build (revo-bootloader, chibios, 10)	56s
build (stm32h7-debug, chibios, 10)	6m 59s
build (fmuv3, chibios, 10)	13m 7s
build (revo-mini, chibios, 10)	10m 5s
build (MatekF405-Wing, chibios, 10)	11m 6s
build (CubeOrange-ODID, chibios, 10)	8m 3s
build (CubeRedPrimary-bootloader, chibios, 10)	56s
build (configure-all, chibios, 10)	9m 14s
build (build-options-defaults-test, chibios, 10)	19m 20s
build (signing, chibios, 10)	8m 19s
build (CubeOrange-PPP, chibios, 10)	6m 31s
build (CubeOrange-SOHW, chibios, 10)	6m 38s
build (Pixhawk6X-PPPGW, chibios, 10)	2m 35s
	2h 30m 27s

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