Move the board specific configurations into its own header file, which
can now be created per board, once it gets tested and validated by the
bootloader.
Signed-off-by: Ricardo Salveti <ricardo.salveti@linaro.org>
The Zephyr build systems makes some assumptions about the directory
layout, and encounters problems if the necessary path contains "../..".
To help this, place the zephyr directory next to the bootutil directory
so that the Makefile can just refer to "../bootutil". This keeps all of
the build artifacts under the proper top-level directory.