The rpi genimage configurations are all identical, except for the boot
partition files, which include:
- Device tree files (*.dtb)
- rpi-firmware files (rpi-firmware/*)
- Kernel image (Image/zImage)
All of these are quite simple to figure out programmatically based on the
content of BINARIES_DIR, so extend post-image.sh to fall back to generating
a genimage configuration based on genimage.cfg.in if a board specific one
does not exist.
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
