GR716: implement flash driver #989

Job	Run time
call-ci / build (armv7a7-imx6ull-evk)	1m 30s
call-ci / build (armv7a9-zynq7000-qemu)	1m 49s
call-ci / build (armv7a9-zynq7000-zedboard)	1m 15s
call-ci / build (armv7a9-zynq7000-zturn)	1m 18s
call-ci / build (armv7m4-stm32l4x6-nucleo)	1m 17s
call-ci / build (armv7m7-imxrt106x-evk)	1m 47s
call-ci / build (armv7m7-imxrt117x-evk)	1m 54s
call-ci / build (host-generic-pc)	1m 12s
call-ci / build (ia32-generic-pc)	1m 22s
call-ci / build (ia32-generic-qemu)	1m 46s
call-ci / build (riscv64-generic-qemu)	1m 8s
call-ci / build (riscv64-generic-spike)	1m 12s
call-ci / run tests on emulators (armv7a9-zynq7000-qemu)	5m 34s
call-ci / run tests on emulators (host-generic-pc)	1m 7s
call-ci / run tests on emulators (ia32-generic-qemu)	3m 55s
call-ci / run tests on hardware (armv7m7-imxrt106x-evk)	2m 9s
call-ci / run tests on hardware (armv7m7-imxrt117x-evk)	2m 17s
call-ci / run tests on hardware (armv7a9-zynq7000-zedboard)	4m 13s
call-ci / run tests on hardware (armv7m4-stm32l4x6-nucleo)	8m 34s
call-ci / notify ci team using e-mail	0s
	45m 19s

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