zephyr: targets: add support for 96b_nitrogen
zephyr: targets: add support for 96b_nitrogen

Signed-off-by: Ricardo Salveti <6fd42f733b6586c555e01d4ff3116fc7e73e7330@linaro.org>

utzig/mcuboot,runtimeco/mcuboot,utzig/mcuboot,tamban01/mcuboot,runtimeco/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot,tamban01/mcuboot,utzig/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot,tamban01/mcuboot,tamban01/mcuboot,utzig/mcuboot,tamban01/mcuboot,runtimeco/mcuboot,runtimeco/mcuboot,utzig/mcuboot,ATmobica/mcuboot,runtimeco/mcuboot