Boot: Introduce rollback protection

- Add image security counter verification (read image security counter
  from the manifest and compare it against the stored security counter)
  as a mandatory part of the image validation process.
- Store the newest value of security counter in a non-volatile (NV)
  counter.
- Add security counter interface to MCUBoot.

Change-Id: I608508e707d01c3777788bc754810407fae610e2
Signed-off-by: David Vincze <david.vincze@arm.com>
9 files changed