Boot: Add version number from command line

- Add an optional command line argument that can be used to set an
image's version number at build-time (using
-DIMAGE_VERSION=maj.min.rev+build) so that the Cmake command within
bl2/ext/mcuboot/MCUBoot.cmake doesn't need to be edited each time the
specified version number needs to be changed
- If the version number is not defined in the command line, use a
default value and automatically increment it in the next build

Signed-off-by: Oliver Swede <oli.swede@arm.com>
Change-Id: I3ff44ffb8219d7ea1a441d918cceb525e7af60f2
7 files changed