drives/flash: use nrfx for nrf

Introduce nrfx_nvmc driver into nordic flash driver implementation.
Thanks to that nrf9160 SoC becomes supported by the driver.

nrfx helps dealing with differences with interface to the NVMC
in secure and non-secure execution modes.

This patch adds NRFX_NVMC Kconfig entry for enabling nrfx_nvmc and
select it along with nordic flash driver.

Disabled UICR operation on nRF9160 for non-secure build
as UICR is not available in this mode.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
9 files changed