Validate slot zero before booting
Validate slot zero before booting

Instead of just checking the upgrade image signature, check the
signature on each boot.  This helps to prevent rogue images being flash
by a means other than the upgrade process.

This feature is controlled by whether BOOTUTIL_VALIDATE_SLOT0 is
defined.

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