RAM/ROM sizes in tools were updated to report entire device size, and in M2351
they were used earlier to report secure/non-secure partition size.
M2351 files are updated to take full RAM/ROM device size and derive secure
and non-secure partition size based on that.
`flash_get_erase_value` is added in hal/TARGET_FLASH_CMSIS_ALGO/flash_common_algo.c
duplicate copy of same function in targets/TARGET_NUVOTON/TARGET_M2351/flash_api.c
resulted in build issues with secure build
In Mbed OS, page size is program unit, which is different than FMC definition.
After fixing page size, we can pass NVSTORE test (mbed-os-features-nvstore-tests-nvstore-functionality).