Build: Move MCUBoot configs from compile time defines to header

Changed the propagation of configurations from being passed by
CMake, to putting them into a dynamically generated header file.

Change-Id: I419121af3762929f18d3b408594d3f5f61528ddb
Signed-off-by: Balint Matyi <Balint.Matyi@arm.com>
diff --git a/bl2/ext/mcuboot/bl2_main.c b/bl2/ext/mcuboot/bl2_main.c
index 6c55ac8..62b93d9 100644
--- a/bl2/ext/mcuboot/bl2_main.c
+++ b/bl2/ext/mcuboot/bl2_main.c
@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 
+#include "mcuboot_config/mcuboot_config.h"
 #include <assert.h>
 #include "bl2_util.h"
 #include "target.h"