Verify the valid RAM address space for RAM_LOADING
Introduce mandatory macros in platform layer region_defs.h or flash_layout: IMAGE_EXECUTE_RAM_START, IMAGE_EXECUTE_RAM_SIZE (or similar with better names)
Add those platforms which support RAM_LOADING
Create a verification function in MCUBoot which checks that image_load_address and image_size from image header is within the execution range
Add checks to target.h to verify the existence of mandatory macros