boot/nxboot: add flush barriers and CRC-validate primary before boot#3428

michallenc merged 3 commits intoapache:masterapache/nuttx-apps:masterfrom

neilberkman:fix/nxboot-power-loss-hardeningneilberkman/nuttx-apps-1:fix/nxboot-power-loss-hardeningCopy head branch name to clipboard