Support for list of images in build info was added with commit
4061311da3 and is used by sysbuild.
Zephyr itself also uses CMake's External Project feature when including
TF-M or TF-A in a Zephyr build.
Populate build info with TF-M / TF-A information when said image is
included in the build.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>