AP_NavEKF2: stop including AP_DAL.h in header #41898

Job	Run time
build (stm32f7, chibios, 10)	12m 20s
build (stm32h7, chibios, 10)	11m 21s
build (fmuv2-plane, chibios, 10)	8m 0s
build (periph-build, chibios, 10)	8m 18s
build (iofirmware, chibios, 10)	4m 2s
build (CubeOrange-bootloader, chibios, 10)	3m 22s
build (fmuv3-bootloader, chibios, 10)	2m 57s
build (revo-bootloader, chibios, 10)	3m 13s
build (stm32h7-debug, chibios, 10)	7m 13s
build (fmuv3, chibios, 10)	15m 47s
build (revo-mini, chibios, 10)	11m 2s
build (MatekF405-Wing, chibios, 10)	11m 42s
build (CubeOrange-ODID, chibios, 10)	10m 2s
build (CubeRedPrimary-bootloader, chibios, 10)	3m 19s
build (configure-all, chibios, 10)	12m 40s
build (build-options-defaults-test, chibios, 10)	25m 52s
build (signing, chibios, 10)	8m 16s
build (CubeOrange-PPP, chibios, 10)	8m 58s
build (CubeOrange-EKF2, chibios, 10)	9m 15s
build (SOHW, chibios, 10)	11m 13s
build (Pixhawk6X-PPPGW, chibios, 10)	3m 42s
build (new-check, chibios, 10)	12m 48s
	3h 25m 22s

Provide feedback