When the machine requires a boot partition, it needs to define the
IMAGE_BOOT_FILES to include the device tree files and Linux kernel
image. This is essentially a generic solution so instead of defining
it for all machines we are providing a default value for them.
To implement that, we borrowed an utility function from Raspberry Pi
BSP. It is copied as is at conf/machine/include/utilities.inc file.
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
