release-note: flash_api_write_protection() deprecation record
release-note: flash_api_write_protection() deprecation record

Added note on deprecation of the API and description of flash
drivers changes.

Signed-off-by: Andrzej Puzdrowski <0222c24e1773dd88269ed0e559909ec9bea3604a@nordicsemi.no>

galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,galak/zephyr,nashif/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,nashif/zephyr,finikorg/zephyr,nashif/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,Vudentz/zephyr,nashif/zephyr,Vudentz/zephyr